The geology of the Claiborne (Eocene) Group of Mississippi as far north as Grenada County

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MANUSCRIPT THESES U n pub lish ed t h e s e s s u b m itte d f o r t h e m a s t e r ’s and d o c t o r ’s d e g re e s and d e p o s i t e d i n t h e L o u is ia n a S t a t e U n i v e r s i t y L i b r a r y a re a v a ila b le f o r in sp e c tio n . r ig h ts o f th e a u th o r.

Use o f any t h e s i s i s l i m i t e d b y t h e

B i b l i o g r a p h i c a l r e f e r e n c e s may be n o te d , b u t

p a s s a g e s may n o t be c o p ie d u n l e s s t h e a u th o r has g iv e n p e r m is s io n . C r e d i t must be g i v e n i n s u b s e q u e n t -w ritte n or p u b lis h e d work# A l i b r a r y w hich borrow s t h i s t h e s i s f o r u se b y i t s c l i e n t e l e i s e x p e c te d t o make s u r e t h a t th e b o rro w e r i s aware o f th e above re s tric tio n s. LOUISIANA STATE UNIVERSITY LIBRARY

1 19-a

THE a ^ Q i m x OF TBS GUXBOIWS; (ECC3KSS) G SW OF MISSISSIPPI AS FAH KORTH AS gltSHABA W R IT

A D is s e r ta tio n ubm itted t e th e Graduate F a cu lty o f th e L ou isian a s t a t s U n iv e r sity and A g r ic u ltu r a l and M echanical C o lleg e i n p a r t ia l f u lf illm e n t o f th e requirem ents f o r th e d egree o f Doctor o f P hilosophy in The School o f Geology

By 3toiI Paul Thomas , Oklahoma a g r ic u ltu r a l and M echanical Co lie g e # 193 M« 3*# L ouisiana a ta te U n iv e r s ity , 1939 June# 1943

UMI Number: DP69232

All rights reserved INFO RM ATIO N TO ALL USERS The quality o f this reproduction is dependent upon the quality of the copy subm itted. In the unlikely event that the author did not send a com plete m anuscript and there are m issing pages, these will be noted. Also, if m aterial had to be removed, a note will indicate the deletion.

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ACKWC'VLSuaM^T T his r ip e r t i s based upon f i e l d work which was dsns f o r tb s Obis O il Company sad i t i s through tb s g e n e r o s ity o f tb s company and t b s bind in te r n e t s f Iir* C* X* Moody and Mr* W* B* JSasry si* i t s g e o lo g ic a l s t a f f th a t t b s papsr was mads p o s sib le *

Dr* H« M* F isk

has been p a r t ic u la r ly h e lp fu l in checking tb s f i e l d work and c r i t i c i s i n g tb s m anuscript*

era* 1* V* Bows* R* J* B u sse ll* R* 0*

R u s s e ll, 0* J# Boy, J* M* HeQuirt and Mr* C* I** Moody bars a l l g iv en o o n s tr u s tiv s c r itic ism *

M iss Jans is u ls t o n Huggins has

a b ly e d ite d tb s manuscript*

ii

TA81& OF O-imWTS Fag# ABSTRACT

v ii

i NTRGBUCTXOH

X

S3K3IiAn FSATUR3S OF TBS AMA MAPPSD

2

FHY8XCCRAFHY

4

CL/ilBORNS STRATIGRAPHY

6

In tr o d u c tio n

6

T a lla h a tta Formation

10

B a sic clayston© member

10

Hesii&ba sand member

19

.inona Greensand

24

Z ilp ha Sbal®

30

K osciusko

Formation

38

/autubbee

Formation

4b

in tr o d u c tio n

4b

iirchusa marl member

47

r c i t e r c h i t t e member

50

Gordon Creek sh a le member

5b

U n d iffe r e n tia te d

57

S h ip p 's

autubbee o f c e n tr a l M is s is s ip p i

Creek sh a le member

59

G eneral fe a tu r e s o f the /autubbee form ation C o ek fieid

Formation

64 68

iii

3-UTIC&LHIF OF TH3 CLAIB0M2 OF MiSSISLIIFl 1'G f& CLAIBCKKS SICTXOK In tro d u c tio n T a lla h a tta Formation Lisbon and Gosport Form ations In tro d u c tio n inona e q u iv a le n t Z i lpba e q u iv a le n t

K oeeiu eio e q u iv a len t autubbee e q u iv a le n t or t y p ic a l Lisbon f a c i e s C oefefield eq u iv a len t YCLIG LSFOSli'XGBAL r*iTTSKK

LIST OF PLATES F lat® I

Geo l o g i c a l Map o f t h e C la ib o rn e Group o f

In back p o e k e t

i s s i s s i p p i a e F a r F o r th a s Grenada County F la te 2

Composite Diagram Showing F a c i e s and T h ic k n e s se s i n t h e b u rfa e e S e c tio n

Changes

xn back p o c k e t

C la ib o rn e

.c ro s s M i s s i s s i p p i LIST uF FIGURES

Fig* i

T a b u la r summary o f t h e H i s t c ry o f

C la ib o rn e

I n back p o c k e t

Nom enclature i n M i s s i s s i p p i Fig* 2

Diagram Showing C o r r e l a t i o n o f C la ib o rn e Group

Page 76

o f E a s te r n M i s s i s s i p p i w ith Type C la ib o rn e se ctio n of

eetern

, labeuaa

LIST OF FKGFIL3S F r e f i le A G e o lo g ic I r o f i l e a lo n g highway ti*

l*

4b

.n back p ocket

From M e rid ia n to Quitman» Glarko and L au d erd ale C o u n tie s , M i s s i s s i p p i p ro file B

G eologic i r o f i l e a lo n g highway U* L* 11

I n back p o c k et

frcm B asic C ity tc V achuta, C larke ana L au derdale C o u n tie s , L ise* P r o f i le C G eologic i r o f i l e a lo n g s t a t e Highway 15

In back p ocket

from P h i l a d e l p h i a to Newton, Neshoba and Newton C o u n tie s , M i s s i s s i p p i I r o f i le D G eo lo gic I r o f i l e a lo n g S t a t e ii.ghw&y 12 from n e a r

It he I to Lc^deuns> a t t a l a

C ounty, M i s s i s s i p p i v

I n back p o c k et

^ r o f i le

G o olegle P r o f i l e a lo n g Highway U* s* 88 from K ilm ic h a e l to th o B l u f f e , C a r r o l l ana Montgomery Counties’, M i s s i s s i p p i

Vi

I n back p o e k e t

abstract

The C la ib o rn e group o f M i s s i s s i p p i i s d iv id e d i n t o s i x f o r m a t io n s i n t h i s r e p o r t* fie ld ,

They a r e (y o u n g e s t t o o l d e s t j i

a u tu b b e e , K o sc iu sk o , Z il p h a ,

Cock*

in o n a and T a ll& h a tta *

The

^ a u tu b b e e fo rm a tio n i s s u b d iv id e d i n t o t h r e e new members i n e a s t e r n M ississip p i*

They a r e (y o u n g e s t t o o l d e s t ) s

P o t t e r c h i t t o member and Archuea m arl*

Gordon Creek s h a l e ,

T h is s u b d i v i s i o n i s n o t

p r a c t i c a b l e i n th e c e n t r a l p a r t o f t h e o u tc ro p b e l t and t h e form a­ t i o n i s n e t d i f f e r e n t i a t e d th e re *

The m arin e

au tu b b ee le n s e s o u t

i n t o non-m arine eanda and s h a l e s i n so u th w e ste rn A t t a l a County, b u t i t s non-m arine e x t e n s i o n , t h e new Z h ip p 'e Creek s h a l e , i s r e c o g n is e d a s f a r n o rth w e s t a s th e a l l u v i a l v a ll e y o f th e M iss­ i s s i p p i R iver*

The T a l l a h a t t a f o r m a tio n i s d iv id e d i n t o th e B a sie

c l a y s t o n e member and th e new Neshoba sand member i n th e e a s t e r n and c e n t r a l p a r t s o f i t s o u te ro p b e l t , b u t t h i s s u b d i v i s i o n be­ comes i n f e a s i b l e i n Grenada County and t h e fo rm a tio n i e n o t d i f ­ f e r e n t i a t e d th e re *

The o t h e r f o u r fo r m a tio n s a r e n o t subdivided*

The h i s t o r y o f t h e te r m in o lo g y , o r i g i n a l d e f i n i t i o n , l i t h e logy, c o n t a c t r e l a t i o n e h i p e , d i s t r i b u t i o n , to p o g r a p h ic e x p r e s s i o n , s o i l s and d e p o e i t i o n a l c o n d i t i o n s o f each o f th e l i t h o l o g i c u n i t s a r e d is c u s s e d *

The a r e a l d i s t r i b u t i o n o f t h e d i f f e r e n t fo r m a tio n s i e

shown on th e g e o lo g ic map ( P l a t e 1} and t h e f a c i e s changes a lo n g s t r i k e a r e ehown on a com posite diagram ( P l a t e 2)* v ii

These two

p l a t e s combined, g iv e a l l o f t h e e s s e n t i a l f e a t u r e s o f t h e C la ib o rn e group i n t h e a r e a mapped*

F iv e s u r f a c e p r o f i l e s a r e a l s o in c lu d e d *

eac h o f t h e C la ib o rn e f o r m a tio n s o f c l i s s i e s i p p i has a l i t h e lo g ic e q u i v a l e n t i n w e s te rn Alabama*

th e s tr a tig r a p h ic re ­

l a t i o n s h i p s o f t h e C la ib o r n e beds i n t h a t a r e a a r e d i s c u s s e d b r i e f l y and t e n t a t i v e c o r r e l a t i o n s w ith t h e ty p e C la ib o rn e s e c t i o n a r e made* The C la ib o rn e group o f c e n t r a l and e a s t e r n M i s s i s s i p p i ex­ h i b i t s a c y c l i c d e p o s i t i o n s ! p a t t e r n which i s s c o n -m a rin e sa nds and s h a l e s ( t o p ) c arb o n ac e o u s s h a l e s o r t r a n s i t i o n f a c i e s m a rin e f a c i e s (b o tto m ) D ie c o n fo rm !tie s o r s t r a t i g r a p h i e b re a k s a t which t h e r e i s evidence o f e r o s io n o c c u r a t th e b a se o f each m arin e s e c t i o n » w hile a l l o t h e r c o n t a c t s a r e conformable*

I t i s b e li e v e d t h a t t h i e p a t t e r n i s caused

by su b s id e n c e und er load and e p e i r o g e n i c movements combined*

v iii

The C laiborne group i s one o f th e fou r groups which c o n s t it u t e th e Eocene s e r i e s o f th e T ertia ry system o f th e so u th ea stern u n ited S ta too*

T his rep ort covers m ost, hut n o t a i l , o f th e C laiborne o f

M is s is s ip p i*

l a r ec en t y ea rs i t has become apparent th a t th e lower

C laiborne beds extend much fa r th e r n orth than i s shewn on th e s t a t e g e o lo g ic a l sap o f 1926 (1}«

I t i s probable th a t they w i l l be found

t o extend to t h e northern s t a t e lin e*

These beds were mapped o n ly

a s f a r north a s th e northern Grenada County lin e during t h i s work#

(1 ) L. w* S te p h en so n , w« K* Logan and G« A# v/aring, "The G ro u n d -w ater K esources o f M i s s i s s i p p i , " U. c* Geoi* curvey a t e r su p p ly Paper 576 (1 9 2 8 ), p l a t e 2 . * * ------- ^ ----- --------

The a r e a mapped e e v e re a p p ro x im a te ly 6,000 sq u a re m ile e and in c lu d e s a l l o r p a r t of f i f t e e n co u n ties s itu a te d in th e c e n tra I p a r t of th e s t a t e of M ississip p i*

i t s g e n e r a l o u t l i n e and p o s i t i o n a r e

sh e en on t h e g e o l o g i c a l map ( P l a t e i}«

The a r e a i s a b e l t c r o s s i n g

t h e s t a t e from t h e M iss ie sip p i-A ia b a m a s t a t e l i n e on t h e s o u t h e a s t t o t h e a l l u v i a l v a l l e y o f t h e M i s s i s s i p p i i d v e r on t h e n o rth w est*

It

a v e r a g e s a b o u t £Q m il e s i n w id th a t t h e Alabama l i n e , g r a d u a l ly i n c r e a s e s n o rth w estw ard t o a maximum w idth o f 60 & iie e a c r o s s A t t a l a and Holmes C o u n tie s and th e n d e c r e a s e s north w ard t o a b o u t 20 m il e s i s w id th i n Grenada County*

T his a r e a was mapped i n a t h i r t e e n

months* p e r i o d b e g in n in g i n t h e s p r i n g o f 1940*

A ll o f i t was

co v ered by t h e w r i t e r e x c e p t t h e C la ib o rn e o u tc ro p a r e a o f n o r t h e r n i a d i s e n County which i s ta k e n from a map by i n c l u d e d i n o r d e r to

make t h e

r* 0* L* koedy and i s

r e g i o n a l map complete*

Xbe C la ib o rn e o u tc ro p p a t t e r n r e f l e c t s t h e r e g i o n a l s t r u c t u r e * The norm al s t r i k e o f t h e beds i n th e extrem e s o u t h e a s t e r n p a r t o f t h e a r e a i s a b o u t 50 d e g re e s w est o f n o rth *

The s t r i k e o f t h e b a s a l

C la ib o r n e c o n ta c t g r a d u a l l y changes no rth w estw ard to a b o u t 10 d e g re e s w est o f n o r t h i n

re n a d a C ounty, w h ile t h e s t r i k e o f t h e u p p e r c o n ta c t

a v e r a g e s a b o u t 35 d e g re e s west o f n o r t h a l l th e way a c r o s s th e s t a te * T h is d i f f e r e n c e i n s t r i k e r e f l e c t s a marked northw estw ard t h ic k e n in g o f t h e C la ib o rn e s e c t i o n from a b o u t 330 f e e t a t t h e M ieeiesip pi-A labam a

3

s t a t e l i n o t o mere th a n 1200 f o o t a t t h e edge o f t h e a l l u v i a l v a l l e y o f t h e k i e a i e e l p p i River* west*

The norm al d ip i s to t h e so u th w e st and

i t ra n g e s from 25 t o 33 f e e t p e r m i l e , b e in g s t e e p e r on t h e

low er beds th a n on t h e upper*

xH T S'X O Q B M 'H Y

The C la ib o rn e group o u tc r o p s l a two p h y s io g r a p h ic re g io n s* ihe g r e a t e r p o r t i o n ©f t h e o u tc ro p l i e s i n t h e a r e a g e n e r a l l y known a e t h e Hearth C e n tr a l H i l l s * a w e l l - d i e e e c t e d ©and h i l l s u p lan d broken by s e v e r a l pronounced © uestas and esca rp m en ts which f o llo w t h e s t r i k e o f t h e beds*

The l o c a l r e l i e f v a r i e s from SO t o 300 f e e t and i s

g r e a t e r on t h e o u tc ro p o f t h e beds i n t h e lower p a r t o f t h e C la ib o rn e s e c t i o n th a n on t h e s e i n t h e upper*

The beds a r e w e ll exposed

th ro u g h o u t t h e a r e a e x c e p t a lo n g t h e w e ste rn b o r d e r where an e x te n ­ s i v e b l a n k e t o f brown s i l t o f t e n o b sc u re s t h e outcrop*

The o n ly

o t h e r s u p e r f i c i a l d e p o s i t s a r e t h e r e c e n t a llu v iu m and q u a te rn ary t e r r a c e m a t e r i a l s a lo n g t h e stream s* The a©conet p h y s io g ra p h ic r e g io n i n which t h e C la ib o rn e beds o u tc r o p i s commonly c a l l e d t h e Loess H i l l s *

T his i s a r e g io n o f

rug ged topography which form s a b e l t from b to I Z m il e s wide a lo n g t h e w e s te rn b o r d e r o f t h e

C la ib o r n e outcrop* The T e r t i a r y i s

c o v ered by t h i c k d e p o s i t s

of q u a te r n a ry sands and g r a v e l s and lo e s s

th ro u g h o u t t h e are a* th e M issie e ip p l

The Loess H i l l s a d jo i n th e a l l u v i a l

v a l l e y of

i v e r and a r e s h a r p l y d e fin e d on t h e w est by a

c o n tin u o u s s e r i e s o f b l u f f s which r i s e a b r u p t l y above th e v a l l e y flo o r*

The t y p i c a l Loess H i l l s to pog raphy marges w ith t y p i c a l sand

h i l l s topograph y e a stw a rd and t h e © a stern boundary i s a r b i t r a r i l y ta k e n ae t h e e a s t e r n l i m i t o f t h e q u a te r n a ry m a n tle d e p o s i t s mapped 4

Si* q ®u F iat® u

T e r tia r y ®xj>®e»r®» ar® Touad ©aiy a ie a g th® stream©

Aa r a v ia e e a ie a g th® b lu f f s Aa t h i s r®gi©at bat they iaeiud® some e f th® b e e t exp©ear®e i a th® etat®*

Q te im m & z r z m m m i INTRODUCTION The t e r a C la ib o r n e U ) was f i r s t used by Conrad i n 1847 f o r t h e " C la ib o r n e sand" exposed a t C la ib o r n e B lu ff* Alabama from which he had d e s c r i b e d a number o f f o e s i l s # e r O ld e r Sosen©” *

He a s s i g n e d i t to th© "Lower

H iig a r d f i r s t i d e n t i f i e d t h e C la ib o rn e group i n

M i e s i e e ip p i i n I860 and d iv id e d i t i n t o a a u p p e r "C a lc are o u s C la ib o r n e g ro u p 1* and a lower " S i l i c e o u s C la ib o rn e gr0Up « #

Beven

year© l a t e r he exclu d ed t h e " s i l i c e o u s C la ib o r n e o r B uhrstone" from t h e C la ib o r n e p r o p e r and h i s r e s t r i c t e d d e f i n i t i o n m e used u n t i l 1894 when H a r r i s i n c l u d e d t h e Buhrston© ( T a l l a h a t t a f o r m a tio n o f l a t e r r e p o r t s ) i n h i s "Lower C la ib o rn e sta g e " *

t h e U nited

S t a t e s G e o lo g ic a l Survey has i n c l u d e d t h e T a l l a h a f t a fo rm a tio n i n t h e C la ib o rn e group s i n c e 1906* a s new g e n e r a l l y a c c e p te d * th e ty p e C la ib o rn e s e c t i o n i s d i v i d e d i n t o t h r e e fo rm a tio n s i n t h e a r e a around C la ib o r n e B l u f f , Alabama*

They are* G ospo rt f o e e i l i f e r o u s sand Lisbon sandy m arl T a lla h & tta fo r m a tio n o r "Buferetone"

(2) M* Grace ? i l m a r t b , "Lexicon o f G eologic Kamos o f th e U n ite d S t a t e s ( i n c l u d i n g A la s k a ),** U. £ . GeojL* Survey B u l l e t i n 893 (1938)* pp# 448-449. 8

7

The group l e o v e r la in by th e Jackson form ation (uppermost geeea e) and l e u n d erlain by th e

l l e o x group (m iddle Soeene)*

F igu re I l e a ta b u la r summary ©f th e h is to r y o f C laiborne nom enclature in M is s is s ip p i*

I t skews th a t th e more modern w riter®

hare d iv id e d th e C laiborne o f M is s is s ip p i in to th r e e form ation s which correspond to th e th r e e ferota tion s o f th e typ e C laiborne s e c tio n o f Alabama.

They area C o ek fieid o r Yegua form ation Lisbon form ation T a ila h a tta form ation In t h i s rep ort th e Lisbon form ation o f th e s e auth ors i s

su b d ivid ed in to fo u r form ation s because i t i s composed o f se v e r a l stappable u n it s which can be tra c ed a c r o ss th e sta te * group 9 th e n , c o n s is t s o f s i x form ations*

The C laiborne

They a r e i

C o ek fieid form ation /autubbee form ation K osciusko form ation Z ilpha sh a le Winona greensand T a iia h a tta form ation The C o ek fieid form ation e f t h i s rep ort in c lu d e s a l l beds above th e predom inantly

a r in e

autubbee form ation and below th e

m arine b a sa l Jackson (Moody's Branch form ation)*

The marine

Wautubhee form ation i s su bd ivid ed in to th r ee new members in ea ster n M is s i s s i p p i , i s u n d iffe r e n tia te d in c e n tr a l M is s is s ip p i> and i s

e x te n d e d n o rth w estw ard i n t o t h e »o«~marine S h ip p ’ s Crook s h a l e member o f t h i s r e p o r t*

The Kosciusko f o r m a tio n i n c l u d e s a l l bods

ab o v e t h e K iip h a s h a l e and bo low t h e Mautubbe© fo rm atio n * Zi. ip ha and

The t o m s

inema a r e u se d a s o r i g i n a l l y d e f in e d by Moore ( I t 40} and

Love ( 1 9 i t ) , r e s p e c t i v e l y *

The T a l l a h a i t a fo rm a tio n i s a iv i d a d i n t o

t h e B a s ie e la y e t o n e member ( Lowe, 1919) and a now member, th e Meeheba sand*

The M e rid ia n s a n d , which i s c o n s id e r e d b a s a l C la ib o rn e by th e

M i s s i s s i p p i § e o l o g i c a l S u rv e y , i s excluded from t h e group* These s u b d i v i s i o n s a r e shown g r a p h i c a l l y on H a t e S, which i s a com posite diagram shewing changes o f f a c i e s and t h i c k n e s s e s e f t h e d i f f e r e n t f e m o t i o n s a lo n g s t r i k e from t h e H e s i s s i p p i - A l a b a m a s t a t e l i n e t o t h e w e ste rn a n d n o r th w e s te r n l i m i t s e f t h e a r e a mapped* The p l a t e i s n e c e s s a r i l y h ig h ly d iagram m atic because i t i s im p o s s ib le t o show t h e t r u e co m p lex ity o f t h e s e c t i o n on a two d im e n sio n a l fig u re*

I t i s c o n s t r u c t e d from d a ta o b ta in e d from highway p r o f i l e s ,

m easured s e c t i o n s , s u r f a c e c o n to u r s , w e ll i n f o r m a tio n and re e o n n a is * sa n e e mapping*

The p l a n e t o which a l l d a t a a r e r e f e r r e d i s th e

Z i Ip b a -T in e n a c o n t a c t , t h e most p e r s i s t e n t and r e l i a b l e c o n ta c t i n th e C la ib o r n e s e c tio n *

H o r i s o n t a l i n t e r v a l s on l l a t e % r e p r e s e n t

d i s t a n c e s a lo n g t h e norm al s t r i k e o f t h e datum p l a n e , w h ile v e r t i c a l i n t e r v a l s i n d i c a t e t h i c k n e s s o f s e c tio n *

The g e o lo g ic s e c t i o n shown

a lo n g any g iv en v e r t i c a l l i n e i s th e ap p ro x im ate s e c t i o n which would be shown by a s u r f a c e g e o l o g i c a l p r o f i l e run p e r p e n d i c u l a r to t h e norm al s t r i k e o f t h e datum p la n e from t h e p o i n t where th e v e r t i c a l l i n e c r o s s e s t h a t plane*

The towns and v i l l a g e s and a few l o c a l i t i e s

on t h e o u tc ro p a r e shown b e s id e v e r t i c a l a rro w s which i n d i c a t e th e

g e o l o g i c a l s e c t i o n exposed, i n and around each* When p r o p e r l y i n t e r p r e t e d , F l a t s 2 shows a l l ©f th e e s s e n t i a l e le m e n ts o f th e C la ib o r n e group i n t h e a r e a mapped*

.& s e t o f exam ples

showing th e u se o f t h e f i g u r e i s ta k e n from t h e a r e a aro u n d th e town o f Newton, Newton County*

The p l a t e shows t h a t th e g e o l o g i c a l s e c t i o n

e xposed i n and a ro u n d th e town ra n g e s from t h e upperm ost few f e e t o f t h e Wautubbee t o sh o u t 60 f e e t up i n t h e C o ek fieid * t h a t th e

I t in d ic a te s

a u tu b b e e s e c t i o n n e a r le w to n i s a b o u t 90 f e e t t h i c k and i s

d i v i s i b l e i n t o t h r e e f a c i e s o r members and t h a t a lo n g th e s t r i k e n o rth w estw ard t h e f o rm a tio n changes f a c i e s a n d becomes th in n e r *

The

f i g u r e a l s o shows t h a t i n t h e a r e a between Newton and D ecatur th e Vautubbee s e c t i o n and t h e u p p e r h a l f o f t h e Kpseiuek© s e c t i o n a r e exposed and t h a t between D ecatur and Neshoba t h e lower K osciusko, a r a t h e r t h i c k s e c t i o n o f Z ilp h a s h a l e w ith a g ree n sa n d bed a t th e t o p , th e

in o n a g rae n sa n d and t h e Neshoba sand a r e exposed* F iv e s e l e c t e d s u r f a c e g e o l o g i c a l p r o f i l e s run a lo n g main

highways t r a v e r s i n g t h e Ciaibern© o u tc ro p b e l t a r e a l s o inclu ded* T h e i r p rim a ry p u rp o se l e f o r use i n i n s p e c t i n g th e C la ib o rn e i n th e field *

N e arly a l l ©f t h e e s s e n t i a l f e a t u r e s o f t h e s e c t i o n a r e

shewn on th e s e p r o f i l e s *

10 'iA U A S U r a FORMATION

in tro d u c tio n The same T a l l a h a t t a f i r s t a p p ea re d i n p r i n t i n an a r t i c l e by D a li (3}.#

I t was s u g g e s te d to him by B* A* Smith t© ta k e t h e p l a c e

o f t h e te rm "B uhrstone* which had a l i t h e l o g i c , r a t h e r th a n a g e o g ra p h ic , c o n n o ta tio n #

The term T a l l a h a t t a has been i n g e n e r a l

u se i n M i s s i s s i p p i s i n c e i t s i n t r o d u c t i o n by Johnson i n 1905 to r e p l a c e H ilg & rd 'e term ^ s i l i c e o u s C laiborne** The t y p i c a l T a i l s h a t t a "bu b reto n e* s e c t i o n , h e r e i n c a l l e d t h e B a s ic c la y s t o n e member, i s w e ll d evelo ped th ro u g h o u t e a s t e r n M i s s i s s i p p i , b ut i n t h e c e n t r a l and w e s te rn p o r t i o n s o f i t s o u tc ro p t h e t y p i c a l f a c i e s i s l a r g e l y r e p la c e d by a sand s e c t i o n c a l l e d t h e fteeboba sand member*

In th e extrem e n o r t h e r n p a r t ©f th e a r e a

mapped t h e e n t i r e s e c t i o n changes f a c i e s and i s c a l l e d u n d i f f e r e n ­ t i a t e d T a l l a h a t t a fo rm a tio n i n t h i s re p o rt* Cl a c t o s e 8 » * » t r I n t r o d u c t i o n - The B a sie c la y s to n e member i s th© s t r a t i g r a p h i c and i i t h o l o g i c e q u i v a l e n t o f th e ty p e s e c t i o n o f th e T a l l a h a t t a forma­ t i o n o f choctaw County, Alabama*

The term B a sic i s used f o r t h i s

s e c t i o n i n p r e f e r e n c e t o T a l l a h a t t a because i t was found n e c e ssa ry t o s e t up a n o th e r member i n M i s s i s s i p p i and th e two members t o g e t h e r l o g i c a l l y c o n s t i t u t e t h e T a l l a h a t t a form atio n#

The name B a sic i s

w e ll e s t a b l i s h e d i n M i s s i s s i p p i l i t e r a t u r e , having been proposed

(3 ) 7# H* D a li, "A Table o f th e Morth American T e r t i a r y Hor ic o n e , C orrelated w ith One Another and w ith Thoee o f Eastern '‘mi0^ ! i 0 n 8 *" Si* *♦ 2*ai* § a s m . M i n &sa* M a £ * . p t . 2 ( 1 8 9 8 ), p . 344*

11 by Lowe i s 19id ( 4 ) and ueed s i n c e i s s e v e r a l M i s s i s s i p p i G e o lo g ic a l Survey b u l l e t i n s *

The ty p e l o c a l i t y i s a deep out en t h e r a i l r o a d

j u e t n o r t h o f B a sic C i t y , a r a i l r o a d s t a t i o n i s n o r t h w e s t e r s C la rk e County* M ie e ie e ip p i*

as

shown o s p r o f i l e Bt a f u l l s e c t i o n SO f e e t

i s t h i c k n e s s i e exposed i s t h i s issnediat© v i c i n i t y #

Xt o v e r l i e s

t h e m icaceous* l i g a i t i c sands o f t h e upperm ost Wilcox (M e rid ia n ) a n d i e o v e r l a i n hy t h e Winona greeneand# b l t h o i e g y - The B a eie member h as t h e most d i s t i n c t i v e l i t h e logy e f any e f t h e beds i e t h e C l a i b o r s e s e c t i o n e f M i s s i s s i p p i #

Xt i e

composed c h i e f l y e f s i l i c e o u s e l a y s t o n e w ith i n t o r b s d a o f s i l i c e o u s s i i t e t e n e and sandston e* e f t h e e l d e r a u th o rs * u s e a s a m il l s t o n e *

These i n d u r a t e d rock© a r e t h e “b u b r s i e n s ”

B uh rsto ne i s any s i l i c e o u s rock s u i t a b l e f o r Very l i t t l e o f t h e m a t e r i a l i n t h e B aeie c o u ld

be so used and t h e t e n s " b u h r e te a e " has been so l o o s e ly a p p l i e d t h a t t h e te n d e n c y e f t h e mere r e c e n t a u t h o r s has been t o drop i t from t h e lite ra tu re # The e lay s to n e o f t h e B a sie f e m e by s u r f a c e i n d u r a t i o n from a d a rk g r e e n i s h gray* somewhat m ic a c e o u s , s i l t y c la y t h a t u s u a lly c o n ta in s s c a t t e r e d p l a n t fragm ents*

The i n d u r a t e d m a t e r i a l l e a

l i g h t - c o l o r e d , b r i t t l e rock which i s rem ark ab le f o r I t s low s p e c i f i c g r a v i t y and which b r e a k s w ith a sub«*ccnehoidai f r a c t u r e #

The con­

t r a c t i o n caused by t h e e v a p o r a tio n o f t h e c o nnate w a ter s h a t t e r s t h e e la y s t o n e i n t o a n g u l a r b lo c k s t h e s u r f a c e s o f which a r e u s u a l l y (4 ) J3« N* Lowe, “M i s s i s s i p p i , Xt© Geology, Geography, Bell© a n d M in e r a l Resources,** Mi s s # Geo I , Survey Bu l l * 14 (1 9 1 9 ), pp* 74-75*

12 s t a i n e d yellow -brow n and which commonXy e x h i b i t a r e g u l a r c o n c e n t r i c band ing e x te n d in g t o t h e c e n t e r o f t h e block*

The c la y s t o n e commonly

c o n t a i n s e m a il l e n s e s , a n g u l a r i n c l u s i o n s and fu o o ic ta i e t r u e t u r e e o f g l a u c o n i t i c s i l t which im p a r t a h e te ro g e n e o u s t e x t u r e t o t h e sedim ent* The s i I t s t o n e i n t e r b e d s o f t h e B a sic member a r e form ed by s u r f a c e i n d u r a t i o n o f a d ark g r e e n i s h gray* l i g n i t i c , a r g i l l a c e o u s * g l a u c o n i t i c , m icaceous* c o a rs e g r a i n e d s i l t * i n c o l o r and o f t e n s t a i n e d by i r o n oxide*

They a r e a l s o l i g h t

The s i l t s t e n e s a r e u s u a l l y

i r r e g u l a r l y i n d u r a t e d and have a c h a r a c t e r i s t i c knobby a p p e a ra n c e on t h e o u tcro p *

I n c l u s i o n s o f c la y and sand s i m i l a r t o t h e i n c l u s i o n s

i n t h e c la y e to n e a r e abundant* S an d sto n es a r e t h e l e a e t common e f t h e i n d u r a t e d beds i n t h e B asic*

th e y a r e s i m i l a r i n g e n e r a l a p p e a ra n c e to th e s i l i s t e n e r

and ran g e from f i n e g r a in e d t o c o a rse grained*

They vary from h ig h ly

g l a u c o n i t i c t o n o n - g l a u c o n i t i c and from s e m i- in d u r a te d to q u a r t s i t i c * Bhale o r b lcc k y c la y s i m i l a r i n l i t h o logy to t h e f r e s h c la y from which t h e cl& ystone a r i s e s b u t la c k in g th e p r o p e r t y o f becoming i n d u r a t e d upon ex p o su re i s abundant i n t h e Basic*

&reensand (5 )

o c c u r s r a r e l y i n t h e member i n t h e form o f t h i n s t r i n g e r s which a r e fou nd b o th a t t h e to p and a t t h e bottom o f t h e s e c tio n * Throughout e a s t e r n k s i s e i e s ip p l t h e base o f th e B a sic member

(5) The term "greeaeattd* i s used in t h i s r e p o r t f o r a eand which c o n t a i n s e v e r 15$, o f g l a u c o n i t e g ra in s * G la u c o n ite - b e a r in g sand c o n ta in i n g l e e s th a n t h a t amount i s c a l l e d " g l a u c o n i t i c sand***

13 i s m arked by a bed e f co&rse g ra in e d * p o o r ly s o r t e d , l i g h t g r e e n i s h g ra y g l a u c o n i t i c ea&d w ith an abundance o f w h ite q u a r t s g r a n u l e s and s m a l l , rounded q u a r t s p e b b le s*

T h is b a s a l sand o f t h e B a sic ra n g e s

up to IQ f e e t i n t h i c k n e s s and g r a d e s upward th ro u g h a g l a u c o n i t i c sandy c la y o r s h a l e i n t o th e o v e rly in g i n d u r a t e d m a t e r i a l* The s t r u c t u r e o f th e B aeie member i s even-bedded and th in -b e d d e d i e t h i c k - b e d d e d , t h e d i f f e r e n t f a c i e s b e in g i n te r b e d d e d th ro u g h o u t th e se c tio n *

The b eds a r e e x t e n s i v e l y j o i n t e d on t h e o u tc ro p and l a r g e ,

v e r t i c a l , d i k e - l i k e b o d ie s e f c la y e to n e a r e o c c a s i o n a l l y seen c u t t i n g a c r o s s th e i n d i v i d u a l beds* i n Newton and Neshoba C o u n tie s l e n s e s o f n e n - g l a u c o n i t i c sand become abu ndant i n t h e Basie*

T his m a t e r i a l i s s t a i n e d r e d , brown,

y e ll o w , p in k and p u r p l e on t h e o u tc ro p and i s f i n s g r a i n e d , m icaceous and w e ll so rte d *

I t s s t r u c t u r e v a r i e s from m assiv e to c re ss-b ed d e d *

P e l l e t s , p a r t i n g s and s t r i n g e r s o f g ray c la y o c c u r i n this? sand* The c h a r a c t e r i s t i c i n d u r a t e d B a sic m a t e r i a l s become p r o g r e s ­ s i v e l y t h i n n e r and mere l e n t i c u l a r n orth w estw ard a lo n g th e s t r i k e u n t i l , i n n o r t h e r n Montgomery and Grenada C o u n tie s , th e o nly rem nants a r e a few l o c a l developm ents o f s o f t , w h ite g l a u c o n i t i c s i listen® * I n te r b e d d e d w ith t h i s s i l i s t e n s and ly in g both above and below i t i n Montgomery County t h e r e i e found a d i s t i n c t i v e b la c k , c a rb o n ac e o u s, s i l t y , m ic a c e o u s, f i s e l e s h a l e which d r i e s o u t i n t o a very l i g h t gray o r w h i t e , e l i g h t l y i n d u r a t e d f l a k y shale*

k s s o c i a t e d w ith t h i s f l a k y

s h a l e a r e p a r t i n g s , s t r i n g e r s and i n t e r b e d s o f m ic ac eo u s, s p a r i n g ly g l a u c o n i t i c t o n o n - g l a u c o n i t i e s i l t a n d sand*

These f l a k y s h a l e s

and a s s o c i a t e d beds re a c h a maximum t h i c k n e s s o f IQO f e e t in th e h i l l s ewet o f G renada, Grenada County, and c o n s t i t u t e a t l e a s t p a r t o f Lowe*s Grenada fo rm a tio n which was long c o n s id e re d to be o f upper

14 file © * ago*

T h is r e l a t i o n s h i p was f i r s t p o i n t e d o u t by t h e a u t h o r s

o f t h e C la ib o r n e and '? ! le e * F i e l d T rip Guidebook o f th e M i s s i s s i p p i C e o lo g ic a l s e c i e t y (M arch, 1940)*

I f t h i s sh ale se c tio n i s p e r s i s t e n t

n o rth w a rd from Grenada County, t h e Grenada beds sh o u ld be c o n s id e re d a member o f t h e t a l l a h a t t a fo rm atio n * In Grenada County t h e f l a k y s h a l e s a r e o v e r l a i n by 3 to 30 f e e t o f l i g h t g r e e n i s h g ray g l a u c o n i t i c sand ©r greens&nd which i a c h a r a c t e r i s e d by an abundance ©f f u c o i d a i s t r u c t u r e s and sm a ll c la y in clu sio n s*

These g l a u c o n i t i c beds s h o u ld be g iv e n t h e rank o f &

new member i n t h e T a l l a h a t t a f o r m a tio n i f th e y a r e p e r s i s t e n t n o rth * ward*

u n t i l more d e t a i l e d work i s done between Grenada and th e

u ia s is s ip p i-T e n n e s e ® ® s t a t e l i n o , i t i s c o n s id e r e d p r e f e r a b l e t o le a v e t h e T a i l a h a t t a s e c t i o n u n d i f f e r e n t i a t e d in Grenada County* Lower C o n tac t * I n t h i s r e p o r t th e base o f th e C laib o rn e group i s p la c e d a t t h e b a se o f t h e B a sic member*

The M i s s i s s i p p i

G e o lo g ic a l S urv ey, f o llo w in g Lowe ( 6 ) , p l a c e s i t a t t h e has® o f th e M erid ian sa n d , a non-m arine sand s e c t i o n which u n d e r l i e s t h e B asic th ro u g h o u t th e a r e a mapped*

The M e rid ia n sand i s named from

e x p o su re s n e a r th e c i t y o f M e rid ia n ,

a u d o rd a le County, M i s s i s s i p p i

and was c o n s id e re d to be a member o f t h e T a i l a h a t t a fo rm a tio n i n s t a t e su rvey p u b l i c a t i o n s u n t i l F o s t e r ( 7 ) r e c e n t l y r a i s e d i t to

S. Hi* Lew©, "Midway and Wilcox Groups" i n wC o a s ta l I l a i n S t r a t i g r a p h y o f M i s s i s s i p p i , P a r t F i r s t , " M iss. Gaol* purvey §EiA» 25 ( 1 9 3 3 ) , p* 1 and p p . 106*106* ( 7 ) V* M* F o s t e r , "L au d e rd ale County M in e ra l R e s o u r c e s ,” Miss* G©ol» Sttrvey B u l l e t i n £ i (1 9 4 0 ) , p . 68*

15 fo rm a tio n ® I rank*

i t i » a maeeiv© t o h i g h ly ereee-be& ded, l i g n .it! c

t o n c B - i i g n i t i e sand which ran g e s up t o 135 f e e t i n t h ic k n e e e and which contain® a few l e s s e e o f g l a u c o n i t i c sand* g re e n a a n d » g l a u ­ c o n i t i c sandy s h a l e and l l g n i f l c s i l t y s h a l e i n C larke and L auderdal© C ounties*

The r e a s o n s f o r e x c lu d in g th e M e rid ia n sand from

t h e C la ib o rn e group a r e s 1* n o n -m arin e

I t i s l i t h o l o g i c a l l y much more s i m i l a r t© th e u n d e rly in g 1 lco x th a n t o th© o v e r l y i n g m arin e i a l l a h & tt a *

i t was

d e p o s i te d u n d e r c o n d it i o n s v ery s i m i l a r to th o s e which p r e v a i l e d th ro u g h o u t most o f 2*

H c o x tim e In t h e e a s t e r n M i s s i s s i p p i are a*

The m arin e T a l l a b a t t a s e c t i o n o v e r l i e s th© M eridian

sand w i t h d i s t i n c t d is c o n fo rr a iiy th ro u g h o u t e a s t e r n M i s s i s s i p p i and w e s te rn 3*

labama# The lower M e rid ia n c o n ta c t change® o v e r s h o r t distan ce®

a lo n g th e s t r i k e from conform able t o l o c a l l y d ie c o n fo rm a b le ( l o c a l e r o s i o n a i channels}* The lower c o n ta c t o f t h e B a sic member i s dl©conformable a s f a r n o rth w e st a s t h e

e a r l M v e r i n Meshoba County#

The d e ta il®

o f th e c o n ta c t and i i t h o l o g y o f t h e u n d e rly in g ana o v e r ly in g beds i n d i c a t e t h a t i t r e p r e s e n t s a em ail e r o s i o n a i and c h r o n o lo g ic a l b re a k in which th e upperm ost few f e e t o f th e lo w -ly in g fcerid ian d e l t a i c p l a i n d e p o s i t s were t r u n c a t e d advance o f t h e T a l l a h a t t a sea*

by w a v e-e ro sio n d u rin g th e

The c o n ta c t i t s e l f i s s h a r p ly d e f i n e d ,

t h e change from non-m arine to m arine f a c i e s o c c u r r i n g w i t h in 6 in c h e s t o 2 f e e t of s e c t i o n i n which t h e two facie® a r e i n t i m a t e l y mixed* Sm all b lo c k s and fragment® o f l l g n i t i c s h a le and quart® pebble®

16 from t h e u n d e r l y i n g bed® a r e found i n t b e b a s a l f e n f e e t o f t h e m arine s e c t i o n an d b ra n c h in g fu eo id & i s t r u c t u r e s from t h e feed® above e x te n d a f o o t o r two down i n t o t b e u n d e r l y i n g n on-m arine sand#

The b a sa l#

p e b b l e - b e a r i n g g l a u c o n i t i c sand o f t h e B a sie member i n e a s t e r n M iss­ i s s i p p i a p p a r e n t l y r e p r e s e n t s a beach d e p o s i t thrown up by t h e waves a lo n g an a d v a n c in g s h o r e * lin e *

The c o n t i n u i t y o f t h i s d e p o s i t i n d i c a t e s

& s t r o n g , unbroken advance th ro u g h o u t t h e a r e a ,

Near

hi l a d e I p h i a ,

t e s h o b a C ounty, t h e r e i s a 10 f o o t le n s o f B a sie m a t e r i a l ly in g a b o u t 10 f e e t below t h e main body o f th e member#

I t a l s o has a

b a s a l , p e b b le - b e a r in g sand and p r o b a b ly r e p r e s e n t s m arine m a t e r i a l s d e p o s i t e d i n a em ail e s t u a r y on t h e m e rid ia n d e l t a i c p l a i n a h ea d o f t h e main advance o f t h e B a sie sea# n o rth w estw ard from t h e r e a r ! R iv e r t h e lower c o n t a c t o f th e B a s ic som ber becomes q u i t e g r a d a t i o n a l and shows l i t t l e ev id e n ce of an e r o e i c a a l break#

The b a s a l , p e b b le - b e a r in g sand i s n o t d ev elo p ed

and t h e t r a n s i t i o n from non-m arine to m arin e f a c i e s o c cu rs th ro u g h 6 t o BO f e e t o f in te r b e d d e d g l a u c o n i t i c sa n d , n o n - g l a u c o n i t i c sa n d , c a rb o n a c e o u s s h a l e and B a s i c - t y p e clay# a p p aren tly n e t

bo

The m arine advance was

s t r o n g i n t h i s a r e a and t h i s c o n ta c t p ro b a b ly

r e p r e s e n t s a g r a d u a l re p la c e m e n t o f non-m arine d e p o s i t i o n by m arine d e p o s i ti o n *

i n t h e Montgem©ry-Grenada County a r e a th e lower T al­

l a h a t t a c o n ta c t i s conform able#

The f l a k y s h a l e s which l i e a t th e

b a s e o f th e T a l l a h a t t a s e c t i o n g rad e downward i n t o th e u n d e rly in g M e rid ia n eand th ro u g h an i n te r b e d d e d eand and s h a le t r a n s i t i o n f a c i e s which ra n g e s up t o 10 f e e t i n t h ic k n e s s #

This c o n ta c t r e p r e s e n t s an

even more g r a d u a l change from non-m arine to m arine c o n d i t i o n s .

17 The B a sic © layetone member a v e ra g e a ab o u t 60 f e e t in th ic k n e ss in e a ste rn M ississip p i* t h a t a r e a i s from 50 to 115 f e e t *

I t s ran g e i n t h i c k n e s s i n

These f i g u r e s a r e comparable w ith

t h e t h i c k n e s s o f t h e f a l l a b a t t a fo r m a tio n i n w e ste rn Alabama where th e a v e r a g e i s 100 f e e t and th e maximum i s 125 f e e t *

I n th e c e n t r a l

p o r t i o n o f i t s o u tc ro p t h e B a sie member becomes t h i n n e r and t h e t h i c k n e s s v a r i e s g r e a t l y o v e r s h o r t d i s t a n c e s a lo n g th e s t r i k e #

The

ra n g e i n t h ic k n e s s h e re i s from 10 t o @0 f e e t and t h e a v e ra g e i s a b o u t 5g f e e t *

Through s o u th e r n and c e n t r a l Montgomery county th e

t h i c k n e s s v a r i e s from 5 to 30 f e e t *

I n th e a r e a a rou nd Grenada th e

t h i c k n e s s o f th e u n d i f i e r e n t i a t e d T a l l a h a t t a s e c t i o n re a c h e s a max-* imum o f a b o u t kcQ f e e t * C ossi I s * Ko d e t a i l e d p a l e o n t o l o g i c a l work hue been don® on th e B a s ic member* but i t i s a p p a r e n t t h a t i t c o n ta in s a la r g e fauna* H ost o f t h e f i n e r g r a in e d ro ck s c o n ta in mold® o f t h i n - e h e i l e d mol"** luges* b u t no l o c a l i t i e s were found where f r e s h f o s s i l s cou ld be c o ll e c t e d *

Many o f th e f o s s i l s i n t h e c la y s t o n e a r e c p aiic ed *

Grim ( 8 ) r e c o r d s b oth diatom s and r a d i o l a r i a i n h i s t h i n s e c tio n s * P i e t r i b u t i o n - Gee d i s t r i b u t i o n o f th e Meehcba eand on page 21* Topographic Sxureeslcm - The B a sic c la y s to n e member forme the s t r o n g Bttbretene C uesta ( 9 ) i n e a s t e r n M i s s i s s i p p i *

Along th e baj&da

o r s t e e p s i d e o f t h e c u e e ta t h e r e i s found some o f th e most rugged ( 6 ) K* 2* Grim* "The Eocene bedim ents of M i s s i s s i p p i * " Miss* Geo I . su rv e y T u l l * 3U (1936)* p p . 152-153* (9 ) Um dm iTenneman, i hyaiggrapjay o f th e G asM pt y.n£AM s t a t e s (Hew York* McGraw-Hill* 1936)* p# 75.

18 to p o g ra p h y i n t b e e n t i r e C o a s ta l > l a i n P rov ince*

Tbo l o c a l r e l i e f

a v e r a g e s a b o u t 175 f o o t and ra n g e s up to 300 fo o t*

On tb o g e n t l e

s l o p s o f tb o c u e s t a t y p i c a l sand b i l l # to p o g rap h y d e v elo p ed on tb o o v e r l y i n g Kosciusko sand i s superim posed upon t h e more rugged c l a y s to n o to p o g ra p h y and t h e a v e ra g e l o c a l r e l i e f i s a b o u t 75 f e e t #

T h is

c u a s t a becomes p r o g r e s s i v e l y l e e s pronounced n orth w estw ard a le n g th e s t r i k e a s t h e c la y s t o n e becomes t h i n n e r u n t i l , i n t h e n o r t h e r n p a r t o f t h e a r e a mapped, i t i s a b s e n t t o very weakly developed* S o i l s - The B a sic c la y s t o n e g iv e s r i s e to f i n e sandy loam and sto n y c la y s o i l s o f t h e

auderd& ie s e r i e s *

They a r e among t h e

p o o r e s t a g r i c u l t u r a l e o i i e formed on t h e C la ib o rn e o u tc ro p i n s tie s 1 s e ip p i*

D e p o s i t io n s ! C o n d itio n s * The p re s e n c e o f th e m in e ra l g l a u ­ c o n i t e and of m arine f o s s i l s a r e g e n e r a l l y re g a rd e d a s prim e f a c i e e v id e n c e f o r & m arine o r i g i n o f t h e a s s o c i a t e d sedim ents*

ih e B a sie

c la y e t o n e a l e e e x h i b i t s e t h e r f e a t u r e s which a r e i n d i c a t i v e e f m arin e d e p o s i t i o n among which a r e th e p e r s i s t e n c e o f th e f a c i e s o v e r 200 m i l e s a lo n g th e s t r i k e , t h e t h i n - b e d d e d , even-bedded s t r u c t u r e and t h e abundance o f f u c o i d a l s t r u c t u r e s *

ion e o f t h e s e f e a t u r e s a r e

common in no n-m arine se d im e n ts i n t h e T e r t i a r y system o f M is s is s ip p i* The t h in - b e d d e d , i e t e r b e d d e d n a t u r e o f th e t a i n body o f th e B a sic member i n d i c a t e s t h a t i t was d e p o s i te d i n q u i e t w a te r i n a p o s i t i o n n e a r enough to t b o r e t h a t s l i g h t changes i n th e g r a i n s i z e o f t h e sedim ent in tr o d u c e d i n t o t h e s e a were rec o rd e d i n t h e i n t e r b e d d in g o f th e c l a y s , s i l t s and sands*

T his d e p e e i t l o n a l a c t i v i t y

was i n t e r r u p t e d i n t h e c e n t r a l p a r t o f th e o u tc ro p a r e a by th e i n t r o -

19 d u c t i e n o f la rg o q u a n t i t i e s o f sand now i n c o r p o r a t e d i n th e s e c t i o n a s t b e Neshoba sand# Tbe u n d i f f e r e n t i a t e d T a l l a h a t t a s e c t i o n o f Grenada County was d e p o s i t e d u n d e r n e a r e r - s h o r e c o n d i t i o n s th a n t h e Basie*

The

f l a k y , c arbo naceous s h a l e s o f th e lower p a r t o f t h a t s e c t i o n a r e p ro b a b ly c o a s t a l wared d e p o s i t s ( s e e D e p o s it! o n e I c o n d i t i o n s o f th e i l p h a sh a le} *

The d e p o s i t i o n o f t h e s e m a t e r i a l s was fo llo w e d by

an encroachm ent o f t h e eea o v e r t h e c o a s t a l marsh and th e d e p o s i t i o n o f th e o v e r l y i n g g l a u c o n i t i c sand and graens&nd* ih e s i l i c e o u s cement which b in d s t h e ro c k s o f th e B a sic i s a p p a r e n t l y prim ary* s i n c e i t i s q u i t e u n i f o r a l y d i s t r i b u t e d th ro u g h 1GG f e e t o f sedi.usn te in e a s t e r n M i s s i s s i p p i *

I t was p ro b a b ly p r e ­

c i p i t a t e d froia t h e se a w a te r u n d e r r e l a t i v e l y q u i e t c o n d itio n s * Neshoba Band Membe r « to * iM iM k *

tf tn * * » « » « * J * v * a »

I n t r o d u c t i o n - O v e rly in g t b e B a sic c la y s to n e and u n d e rly in g t h e Tinona groeneand th ro u g h o u t th e c e n t r a l and n o r t h e r n p o r t i o n s o f th e a r e a mapped* t h e r e i s a s e c t i o n o f n o n - g i a u c o n i t i e to s p a r i n g ly g l a u c o n i t i c eand which has h e r e t o f o r e been c o n s id e re d t o bo lower wineaa*

T h is eand s e c t i o n i s a u s e f u l mapping u n i t and i t i s h e r e i n

named th e Neshoba sand from t y p i c a l e x p o su re s i n and around t h e v i l ­ la g e o f Neshoba* Neshoba County*

The ty p e s e c t i o n i s d e s ig n a te d a s

t h a t shewn ly in g above th e B a sle c la y s t o n e and below th e Winona g ro en e an d on P r o f i l e C a lo n g th e p r e s e n t highway th ro u g h Keehoba* Tbe Neshoba eand i s c o n s id e r e d t o be a member o f t h e T a l l a ­ h a t t a fo rm a tio n because* U

I t i s t h e s t r a t i g r a p h i c e q u i v a l e n t of p a r t o f th e typst

ZQ

B a s ie clayeton© s e c t i o n and s i p a r t o f t b e ty p e T a l l a h a t t a s e c t i o n o f Choctaw C ou nty | Alabama*

T h is r e l a t i o n s h i p i s i l l u s t r a t e d on

P l a t e 2 where t b e o v e r l y i n g Winona g re e n sa n d i s shewn m a i n t a i n in g a c o n s t a n t t h i c k n e s s and l i t h e l o g y a c r o s s th e a r e a where t h e Neshoba l e n s e s o u t i n t o th e Basie* 2*

The ^eehoba eand i s o v e r l a i n and u n d e r l a i n by t y p i c a l

B a s ie m a t e r i a l i n Newton and L auderdale C ounties* 3*

The Keshoba and B a sie f a c i e s a r e i n t i m a t e l y i n t e r l e a v e d

o v e r a wide a r e a and th e t h i e k n e e s o f t h e fteeheba f l a e t u a t e e i n ­ v e r s e l y w ith tb e t h i e k n e e s o f t h e Basie* A t bo logy - The Kesboba sand i s composed o f n c m - g l a u c c n i t ic t o s p a r i n g l y g l a u c o n i t i c , n e n - f o s e i l i f e r o u e * m arine sa nds which a r e t y p i c a l l y w e ll s o r t e d , f i n e g r a i n e d and m icaceous and which vary i n s t r u c t u r e from m assive t o i r r e g u l a r l y bedded t o cre ss-b ed d e d *

hen

f r e s h , t h e sa n d s a r e w h i t e , b u t on t h e o u tc ro p th e y a r e u s u a l l y s t a i n e d r e d , brown, y e llo w , p u r p l e and m ottled *

Tbe sands i n th e

u p p e r 5 to 15 f e e t o f t h e member a r e n o rm ally q u i t e d i f f e r e n t i n a p p e a ra n c e from th e sa n d s i n th e rem a in d e r o f the s e c tio n *

They a r e

d a r k , b r i c k re d in c o l o r , h ig h ly a rg illa c e o u s ? , medium g r a in e d and p o o r l y so rte d *

T h e ir h igh c la y c o n te n t and dark c o lo r a r e d e riv e d

from th e o v e rly in g w e ath e re d '.Viacom greeneand th ro u g h th e a c t i o n o f p e r c o l a t i n g groun d-w ater#

Qreeneands and g l a u c o n i t i c sa nds a re

o c c a s i o n a l l y found i n th e liesheba*

They a r e lo c a l c o n c e n tr a te s of

g l a u c o n i t e which g rad e l a t e r a l l y and v e r t i c a l l y i n to n o n - g l a u c o n i t i c sands* Gray c la y i s ab u n d an t in t b e i eehoba l a th e form o f p e l l e t s , p a r t i n g s , s t r i n g e r s and le n s e s i n th e sands*

impure b e n to n i t e and

2.x

b e n t o n i t i c c la y s a r e found a t o r a o a r t h e top o f th e member i n A t t a l a a n d G renada C ounties*

I n n o r t h e a s t e r n Newton and n o r th w e e te r n xauder*

d a l e C o u n tie s t h i n * d is c o n tin u o u s le n s e s o f t y p i c a l g r e e n i s h gray* B a s ic * ty p e s l a y and s h a l e o c c u r a t th e to p o f t h e matcher*

in

n o r t h e r n Montgomery and Grenada C o u n tie s th e tteebeb* s e c t i o n t h i n e and shews a d e c id e d change o f f a c i e s *

Carbonaceous c la y s and s h a l e s

become abundant a s l e n s e s and p a r t i n g s i n th e g l a u c o n i t i c t o ncm-gi&ue e n i t i c , m icaceous san ds and s i l t s and a t a few l o c a l i t i e s d i s c o n t i n ­ uous* B a s ie * ty p e s i l t s t o n e le d g e s o ccur w i t h in t h e se c tio n *

These

sa n d s and s h a l e s a r e i n c l u d e d i n t h e u n d i f f e r e n t i a t e d T a l i a h a t t a s e c t i o n o f Grenada County* Lower C o n tact * The Beshoba sand l i e s conform ably upon th e B a sic c la y s to n e *

Throughout t h e c e n t r a l p a r t o f t h e T a l i a h a t t a out*

crop b e l t , th e r e d sa n d s o f t h e Neshoba u s u a l l y r e s t d i r e c t l y upon t y p i c a l B a sie c la y o r s h a l e and o c c a s i o n a l l y th e y l i e upon e lite to n © o r san d sto n e*

The c o n ta c t i e n o rm ally s h a r p ly d e fin e d * t h e r e b e in g

no i e t e r b e d d i n g o f t b e two f a c i e s *

In t h e Uontgomery-Granada County

a r e a t h e c o n ta c t i s more g r a d a t i o n a l and i e u s u a l l y marked by an i n t e r b e d d i n g o f t h e two f a c i e e * D i s t r i b u t i o n * The o u tc ro p a r e a s o f th e B asic c la y s to n e and Neshoba eand members a r e grouped t o g e t h e r a s T a l i a h a t t a fo rm a tio n on t h e geo l o g i c a l map ( P l a t e 1 ) b ecau se i t s email sea le l i m i t s th e amount o f d e t a i l which can b? shown*

a stu d y of Figure© 1 and 2 i n

c o n ju n c tio n w i l l g iv e th e ap p ro x im ate d i s t r i b u t i o n of th e two f a c i e s * I n n o r t h e a s t e r n C larke and s o u t h e a s t e r n B auderdaie C o unties th e B asle c o n s t i t u t e s th e e n t i r e T a l i a h a t t a fo rm a tio n and t h e o u tcro p a r e a i s

22 ft v e ry n arro w and i r r e g u l a r b e l t w ith numerous to p o g r a p h ic o u t l i e r © w hich r e f l e c t © t h e marked developm ent o f th e B u hrston e C ueeta and t h e s h a r p n e s s o f t h e b a ja d a i n t h a t are a*

N orthw estw ard a lo n g th e

s t r i k e t h e T a l l a h a t t a o u tc r o p widens to an a v e ra g e w id th o f a b o u t 6 m il e e and becomes le e s i r r e g u l a r and t h e Neshoba eand o u tc ro p a r e a becomes pred o m in an t ov er th e B a s ic o u tcro p area* T opographic jta n rs e e io n * Throughout meet o f i t s o u tcro p th e Neshoba eand g i v e s r i s e t o a rugged eand h i l l s to p o g rap h y i n which t h e l o c a l r e l i e f average© a b o u t ?S f e e t*

£ la r a t i o n s on t h i s o u tc ro p

a r e i n g e n e r a l q u i t e h ig h b ecause i t l i e s between th e s t r o n g Buhrs to n e Cue e t a on t h e e a s t and t h e we U n d e v elo p e d c u e s t a on th e

jinona

g ro en ean d t o t h e west* S o i l s - The Neshoba sand g iv e s r i s e to loose* l i g h t g ra y o r l i g h t brown f i n e sandy loam and f i n e ©and ©oils*

The t o p - s o i l range©

up t o I f o o t i n t h i c k n e s s and t h e s u b - s o l i * which i s a r e d d i s h brown o r m o tt l e d c la y e y sand o r sandy clay* ra n g e s up to 6 f e e t in th ic k n e s s * Tbeee s o i l s a r e mapped a s * u sto n o r some c l o s e l y a l l i e d s o i l s e r i e s * such aa G r e e n v ille * c ra n g e b u rg o r Norfolk*

They a r e f a i r l y good

s o i l s f o r g e n e r a l a g r i c u l t u r a l purpose©* ^ © p o s itio n a l C o n d itle n s - The manner in which th e Neshoba sand i s i n t e r l e n e e d w ith t h e B a sic c la y s to n e * t h e s l i g h t l y g l a u c o n i t i c n a t u r e of t h e beds ana t h e canform able n a tu r e o f th e lower c o n ta c t i n d i c a t e a u a r i a a o r i g i n f o r t h e Neshoba*

The i r r e g u l a r bedding and

c r c e s - b e d a i n g p o i n t to a n e a r - s n o r e s i t e where current© were a c tiv e * c u rin g th e tim e i n which t h e upper B a sic clay® and s i l t © were b e in g d e p o s i t e d i n e a s t e r n i i i e e i s s i p p i * an abundance of sand was i n t r o -

23 dueed i n t b e s e a i n t h e c e n t r a l and n o r t h e r n p a r t e o f t h e a r e a mapped and wee i n e o r p o r a t e d i n t h e s e c t i o n a s th e fteshoba*

C o n d itio n s i n

t h e Keehoba se a were u n fa v o ra b le to th e p r e c i p i t a t i o n o f s i l i c e o u s m a t e r i a l , p ro b a b ly b e in g to e n e a r - s h o r e i n a g i t a t e d w afers* m arin e l i f e was im p o v e rish e d i n th e

-ith e r

eohoba se a o r condition® f o r i t s

p r e s e r v a t i o n were e x tre m e ly u n f a v o r a b le b ecau se t h e r e i s no f o s s i l e v id e n c e o f i t s e x is te n c e *

WIIKSiA GE3SWSANB I n t r o d u c t i o n * The name

in o n a w&® p ro p o se d toy low® { AOJ i n

IS 19 f o r groeneand® which a r e w e l l exposed n e a r t h e town ©£ Winona, Montgomery County*

Hie o r i g i n a l d e f i n i t i o n ie a

"The ? in e n a eand a® found, i n t h e w e s te rn p a r t o f it® o u t c r o p , e s p e c i a l l y w e l l d ev elo p ed aro u n d Winona, Vaiden and e a s tw a r d i n t o a d j a c e n t c o u n t i e s , c o n sist® o f h ig h ly g l a u c o n i t i c sa n d s and c la y e y eand® t h a t w e a th e r t o an i n t e n s e I n d i a n r e d c o l o r where exposed a t t b e s u rfa c e * T h is m a t e r i a l i s m arine i n o r i g i n and l o c a l l y a b u n d a n tly £oeei life ro u s* On t b e S ou th ern R a il r o a d tooth e a s t and w e st o f Winona, a r e c h a r a c t e r i s t i c n o t a b l e d ep o sit® o f t h i s m a t e r i a l , t h a t a t E l l i o t t , t h r e e m ile s e a s t o f Winona, toeing e s p e c i a l l y s t r i k i n g * From Winona southw ard on t h e I l l i n o i s C e n tr a l R a ilr o a d f r e q u e n t o u tc r e p e o f t h e m a t e r i a l a r e seen a® f a r s o u th a s ¥a id e n and B eatty* The t h i e k n e e s o f t h i s d i v i s i o n o f t h e I f e l i a h a t t a i n n o r th w e s t M i s s i s s i p p i i s e s t im a t e d t o toe a p p ro x im a te ly 350 f e e t * 11 A lthough Lowe's e s tim a te d t h i c k n e s s i s s e v e r a l tim e s to o h ig h and th e u p p e r and lower lim it® of th e

inorm a r e n o t drawn,

t h e d e s c r i p t i o n o f th e l i t h o l o g y and tb e l o c a l i t i e s m entioned s a t i s * f a c t o r ! l y d e l i m i t th e fo rm ation* Lowe e r r o n e o u s l y c o n s id e r e d t h e

in o n a to toe t h e lower member

of th e T a l l a h a t t a f o r m a tio n and c o r r e l a t e d i t w ith t h e M eridian eand o f e a s te rn M ississip p i*

lie (1 1) had p r e v i o u s ly a p p l i e d th e name

E n t e r p r i s e to a g ree n sa n d exposed in t h e town o f e n t e r p r i s e * Clarke County, and had c o n s id e r e d i t to be th e b a s a l member of th e Lisbon fo rm atio n*

Cooxe (IB ) was t b e f i r s t to re c o g n is e t h a t t h e greensand®

( 1 0 ) E* K* Lowe, " ^ i e s i e s i p p i , It® Geology, Geography, Roil® and M in e ra l R e s o u rc e s ," foies* Oeol* survey Bull*. 14 ( 1 9 1 9 ) , p* 73* (1 1 ) and M i n e r a l

2* K* Lowe, " M i s s i s s i p p i , I t s Gee lo g y , Geography, doll® .© sources," Ml e ^ G e elf Guryev Bull* Ik (1915}, p* 76*

( Ik) C* tfythe Cooke, ' C o r r e l a t i o n of t h e ocene formation® o f M i s s i s s i p p i and ;*labsm a,” U*. USSIil S tm X . t£g£s. L&fcg£ 142=1 ( 192*5 j , p* 135*

exposed a t

/ino na and e n t e r p r i s e a r e p a r t s o f i d s same f o r m a tio n and

be d ro p p ed t b s term e n t e r p r i s e b e ca u se i t was p reoccup ied* m ost l a t e r w orkers have c o n s id e r e d t b e

Cooks and

in o n a to i n c l u d e a i l o f th e

bed s above t b e B a sic member and below tb e E ilp h a sh a le*

m th is

r e p o r t t h e t e r n Ninons, i e r e s t r i c t e d to t h o s e g re e n sands to which t b e name was o r i g i n a l l y a p p l i e d and th e u n d e rly in g sands a r e i n c lu d e d i n t h e Neshoba* if.o st a u th o r s have c o n s id e r e d th e vinona g re e n sand to be a member o f e i t h e r t h e T a l l a h a t t a o r 14.ebon f o r m a t io n s .

I t ie raised

t o fo rst& tio n a i rank i n t h i s r e p o r t because i t i s a very d i s t i n c t i v e l i t h e l o g i c a l u n i t which has a wide a r e a l d i s t r i b u t i o n » i t b e in g th e o nly fo rm a tio n i n t b e C la ib o rn e group which e x te n d s a l l th e way a c r o s s t b e s t a t e w ith o u t e x te n s i v e f a c i e s changes* L ith e lo g y • The Winona fo rm a tio n i s composed of gro en eande and g l a u c o n i t i c sands which vary from l i g h t g r e e n i s h g ray to dark g ree n when f r e e h and which w e ath e r to a d i s t i n c t i v e d a r k , b r i c k re d c o lo r* t o 9 G£*

The g l a u c o n i t e c o n te n t o f th e Winona sande ran g es from IQ There i e a n o t i c e a b l e ten d e n cy f o r th e g l a u c o n it e g r a i n s

t o be c o a r s e r th a n th e q u a r t s g r a i n s and th e sands a r e u s u a l l y p o o r ly s o r t e d .

These g ree t;san d s and g l a u c o n i t i c sands a r e u n u s u a lly

c o a r s e g r a in e d f o r sands o f t h i s t y p e , a lth o u g h t h e median g r a i n s i r e i s r a r e l y l a r g e r th a n medium ©and e ls e *

The © tr u c tu re of th e

sand© i© commonly &aagive to p o o rly bedded and o c c a s i o n a l l y tfaic-b e d d ad and even-bedded* ra re ly *

In e a s te rn

h igh a n g le c ro s s -b e d d in g occur©

i s e is e i p p i th e

in o n a becomes l e n t i c u l a r and

t h i n and le n s e s o f t o n - g l a u c c n i t i c , m assive to h ig h ly c re s s - b e d d e d

26 sand o c c u r i n th e fo r m a tio n a t a few l o c a l i t i e s * common I s t h e g ree n sa n d e i n t h a t area#

q u a r t a pebble© a r e

Clay o c c u r & i n t h e 'rinona

sa n d s a s f o r m le s s i n c l u s i o n s an d t h e r e a r e a few e x p o s u re s where t h i n l e s s e e o f b l a c k , c arb o n ac e o u s s h a l e o c c u r i n t h e s e c tio n *

The

vicuna sands a r e l o c a l l y c a l c a r e o u s and f o s s i l i f e r o u s le n s e s a r e common, b u t s u r f a c e l o c a l i t i e s where f r e s h f o s s i l s can be c o l l e c t e d a r e r a re # S i d e r it e o ccurs in th e

.inona a s t h i n beds o u tc r o p p in g a s

le d g e s and a s i s o l a t e d c o n c r e t i o n a r y m asses o f dense# l i g h t brow nish gray m a t e r i a l , but i t I s r a r e l y seen i n t h e f r e s h s t a t e on th e s u r f a c e b e ca u se i t w e a th e rs r e a d i l y t o l i m o n i t i c c ia y s t o n e o r ir o n s to n e *

It

i s p a r t i c u l a r l y a b u n d an t n e a r th e to p o f th e fo rm a tio n i n th e n o r t h e r n p a r t c f t h e a r o a and i t s f i r s t a p p e a ra n c e i n w e ll samples can u s u a l l y be ta k e n a s t h e to p o f t h e v inona*

T his f a c t i s o f p a r t i c u l a r v a lu e

i n t h e i n t e r p r e t a t i o n o f o ld w a te r w e ll le g s where e i d e r i t e i s

logged

a s "rock*’* The d e ep ly w eathered

in e n a o u tcro p i s marked by an abundance

o f c o n c r e tio n a r y l i m o n i t i c s a n d s to n e b o d ies which e x h i b i t a i l shapes and s i z e s and d e g re e s o f i n d u r a t io n *

Ifeey a r e very u s e f u l i n d i c a t o r s

f o r th e w eath ered o u tc ro p and f o r both th e upper and low er c o n ta c ts* The upper c o n ta c t l i e s im m ed iately above t h e upperm ost c o n c r e tio n a r y led g e and t h e b a s a l c o n ta c t i e u s u a l l y n o t f a r below th e lowermost c o n cretio n ary m a te ria l* ower C o n tac t • Th© V in c n a-T alla h & tta c o n ta c t i s conform able and s h a r p l y defin ed*

The d e t a i l s o f th e c o n ta c t d i f f e r somewhat

w ith t h e n a t u r e o f t h e u n d e rly in g m a t e r i a l*

The c o n ta c t between th©

in o n a g re e n sa n a and th e B asic eiayeton© i n e a s t e r n T i e s i s e i p p i i e

27 s l i g h t l y i r r e g u l a r and t h e r e i s a h e te ro g e n e o u s m ixing o i t h e two f a c i e s a t th e c o n ta c t p ro p er* h u t t h e u nifo rm t h i c k n e s s a n a p e r s i s ­ t e n c e c£ t h e upperm ost b a s i s beds i n i n d i v i d u a l e x p o s u re s d i s p r o v e s any s i g n i f i c a n t t r u n c a t i o n o f b a s i c m a t e r i a l s *

B o rin g s and p o c k e ts

f i l i e d w ith m a t e r i a l from above e x tend a lew I n c h e s down i n t o t h e u n d e r ly in g beds*

S e v e ra l a u t h o r s have c o n s id e r e d t h i s c o n t a c t to be

u s conform able o r a is c o n f o ratable upon t h i s e v id e n c e » b u t such c o n t a c t s a r e common between t h e d i f f e r e n t beds i n many m arine se q u en c es and th e y a p p a r e n t l y have l i t t l e s i g n i f i c a n c e *

At l e a s t seven such b re a k s

o c c u r i n 140 f e e t o f f a i r l y homogeneous L isbon sandy m a r l i n th© k i t t l e s t a v e Creek s e c t i o n n e a r Jackson* C lark e County* Alabama. The homogeneity o f t h i s s e c t i o n preclude© th e e x i s t e n c e o f seven l a r g e d e p o s itio n © I b r e a k s d u rin g ^ is b o n tim e and t h e contact® must r e p r e s e n t m inor b re a k s i n s e d im e n ta tio n * o r d ia s te m s in which sub* m arine e r o s i o n was a c tiv e * i n t h e a r e a where th e Winona groeneand o v e r l i e s t h e Neshoba sa n d t h e c o n ta c t sho&e more v a r i a t i o n *

At some exposure© th e two

f a c i e s a r e i n t i m a t e l y mixed th ro u g h two o r t h r e e f e e t o f s e c t i o n and sm a ll le n s e s o f g l a u c o n i t i c m a t e r i a l a r e found s e v e r a l f e e t below t h e main body o f th e greensand*

The g l a u c o n i t e i e abundant and i r ­

r e g u l a r l y d i s t r i b u t e d a t and im m ediately below t h e c o n ta c t and be* comes i n c r e a s i n g l y r a r e downward*

t h e r e i s no reaso n to b e li e v e

t h a t t h i s c o n ta c t does not r e p r e s e n t t h e same s e t o f c o n d it i o n s a s t h e '"in o n a-B a eic c o n ta c t in e a s t e r n ::;i» e ise ip p i*

The d iffe re n c e ® i n

t h e d e t a i l s a r e p ro b ab ly due t o t h e c o m p a ra tiv e ly u n c o n s o lid a te d n a t u r e of th e i.eehoba sand a s compared w ith th e S a s ic clays* e t h e r o u t c r o p s t h e t r a n s i t i o n from

in o n a to fteshoha f a c i e s i e

At

u n if o r m ly g r a d a t i o n a l th ro u g h s e v e r a l f o o t o f t r a n s i t i o n bode#

T his

ty p e o f c o n ta c t a p p a r e n t l y r e p r e s e n t s a g ra d u a l* u n iform change i n th© ty p e of m a t e r i a l b e in g d e p o site d * T h ic k n ess ■* The t h i c k n e s s o f th e from 0 t o 50 f e e t *

in o n a g roeneand v a r i e s

Over most o f th© a r e a mapped At i s c o n s i s t e n t l y

a b o u t 25 f e e t and v a r i a t i o n s o f o v e r 10 f e e t from t h a t f i g u r e a r e r a re *

Th© fo r m a tio n i e t h i n and p o o r ly d evelo ped i n C la r k s and

L au d e rd ale c o u n tie s * ra n g in g i n t h i e k n e e s from 0 to 20 f e e t and a v e r a g i n g a b o u t 10 f e e t *

The few p l a c e s where i t i s a b s e n t seem

t o be oases o f sim p le n o n - d e p o s i ti o n o f t h e i a c i e e * developm ent of th e

The maximum

im m a greensan d o c c u rs in t h e g e n e r a l v i c i n i t y

o f th e ty p e lo c a lity * o s o i l s - The TAnona g ree n sa n d c o n ta in s two e x c e l l e n t in d e x fo ss ils*

They a r e Qrfcrea s e l l a s f o r m l e m r « ii.sbonene.ie a n a T ro -

g c u te 1l a m i g s i s g l o a l e n e i a *

The fo rm a tio n has a r a t h e r la r g e and

v a r l e a fa u n a which i n c l u d e s pelecypo& s, g a stro p o d s* e ch in o id s* c ra b s* s h a r k 's t e e t h * f o r a m i n i f e r e and o stra c o d e * but t h e r e a r e v e ry few l o c a l i t i e s i n th e s t a t e le c te d *

h e re f r e s h m a t e r i a l can be c o l ­

•h© b e s t l o c a l i t i e s a r e i n and aroun d th© town o f .I n te r -

p r i s e * C lark? county*

o s i e r {13} l i s t s 4 2 -specie© of m a a r o f o s g i is

i d e n t i f i e d by Cooka from s e v e r a l l o c a l i t i e s i n t h i s v i c i n i t y * m ic ro fa u n a o f t h e

I he

in o n a has n o t been s t u d i e d i n d e t a i l *

D i s t r i b u t i o n - See D i s t r i b u t i o n o f th© /.Alpha on page 35* Tooogranhie e x p re s s io n - The Tinuna groeneand has l i t t l e o r no t o p o g r a p h ic e x p r e s s io n i n e a s t e r n r i i e e l s s i p p i whore i t o v e r l i e s {13) V* M. F o s te r * op* g i t ** pp* 62*64*

ill© S u s ie b e ca u se i t i® p o o rly d ev elo p ed and i t s i n f l u e n c e i s o v e r shadowed by t h a t o f th® B a sic c la y stone# a r e a sa p p e d th®

X» th© c e n t r a l p a r t o f th®

in o n a forme a secon dary c u e s ta ly in g t o th® w est o f

th© s t r o n g e r Bahrston© C u e s ta , b a t n o rth w estw ard a lo n g th© s t r i k e th e c u e s t a d e v e lo p e d on th e Winona becomes more Marked a s th e B ah rsto n e C ueeta grows weaker and i n t h e n o r t h e r n p a r t o f t h e a r e a t h e

in o n a

c u e e ta i s th e dominant to p o g r a p h ic f e a t u r e * S o i l s * The Winona g ro en eand g iv e s r i s e to a very d i s t i n c t i v e l i g h t brown to g ra y sandy loam s o i l o f c o n s i d e r a b le f e r t i l i t y #

The

t o p - s o i l i e th in * ra n g in g up to © in c h e s i n t h i c k n e s s , w h ile th e e u b v s e i i i s from 16 to £4 in c h e s i n t h i c k n e s s and i e a red to r e d d i s h brown, f r i a b l e sandy c la y which u s u a l l y c o n t a i n s frag m e n ts o f sand ­ s to n e c o n c r e tio n s *

T his s o i l i e known a s th e Macogdochee o r some

c lo s e ly a l l i e d se ries* D e p o s i t io n s I C o n d itio n s - The o y s t e r s , eohineid® and c ra b s p r e s e n t a s f o s s i l s i n th e Winona groeneand i n d i c a t e a sh a llo w * w a te r, near-*shore environm ent f o r i t s d e p o s itio n *

Buch a n environm ent

would have c u r r e n t s c a p a b le o f h a n d lin g such c o a r s e - g r a i n e d m a te r ia l* Winona d e p o s i t i o n r e p r e s e n t e d an epoch of e b a llo w -w a te r c o n d it i o n s which c lo s e d t h e c y c le o f m arin e d e p o s i t i o n i n i t i a t e d by th© advance o f t h e T & ilah& tta sea*

SILPH& SHal® i n t r o d u c t i o n * The t e r n £Alpha f i r s t a p p e a re d i n p r i n t in th© guidebook f o r th© C la ib o rn e and Geo l o g i c a l S o c ie ty (March# IM u )* on page 3*

i l e e x F i e l d T rip o f th e M ise is-sip p i The o r i g i n a l d e f i n i t i o n appear©

I t Ass

**A w ork able bed ©f gray w h ite and c h o c o la te brown clay# having a t h i c k n e s s o f a b o u t 60 f e e t # was found to 11 © between t h e in o n a and t h e Kosciusko i n b e r t h C e n tr a l T ia s A e r lp p i in C a r ro ll# Grenada# and ^ t t a i a C ounties* * r* Raymond Moore# fo rm e rly w ith th e A rkansas F u e l O il Company# found t h i s t o be a good key horixon# and su g g e ste d t h e name o f z il p b a # from Zilpfca iU v e r i n a t t a i n County*^ a lth o u g h

term h a u n e v e r been f o r m a lly defined, by it©

a u th o r # th e c o n d it i o n s a r e such t h a t th e r e can be l i t t l e r e g a r d i n g t h e beds t o o h ie h i t was f i r s t a p p lie d *

c o n fu s io n

The name & iipha

i s i n common u s e in k i e s l e e i p p i a t t h e p r e s e n t tim e and i s used i n t h i s r e p o r t a s a©f i n e a i n th e guidebook*

Th© Ai Ip ha s h a le doe© n o t

o u tc r o p on 2 i l p h a c re ek ( o r R iv e r ; p ro p er# b u t thee© bed© re a c h t h e i r maximum development in t h a t g e n e r a l a re a *

-he b e s t exposure

o f t h e s h a l e in th© v i c i n i t y o f Z ilp h a Creek i s found a lo n g the c o u n ty ro a d a t d u c k s n o rt H i l l and t h a t l o c a l i t y i s h e r e i n s e t up a s th© ty p e l o c a l i t y o f th© z i l p h a s h a le i n o r d e r to a v o ia any c o n fu s io n i n tn e f u tu r e *

The ty p e s e c t i o n i s d e s c rib e d u nd er ^ ith e lo g y *

tfte Z ilp b a s h a le i s faAven fo m a t r o n a l rank i n t h i s r e p o r t becauses L*

i t i s & d i s t i n c t i v e 11t h o l o g i c a l u n i t which can be

t r a c e d w i t h o u t s e r i o u s i n t e r r u p t i o n a c r o s s th e s t a t e of h. i s s i e s i p p i * Z*

d i v i n g i t t h e rank o f a taember a lo n g with t h e

inona o r

Kosciusko would n e c e s s i t a t e th© i n t r o d u c t i o n o f a new f o r m a t i o n a l name# sine© both of t h o s e terms a r e r e s t r i c t e d to o t n e r beds and

31 s h o u ld n o t ho expanded t o in c l u d e th o Li Ipha s e c tio n * L itbolo& y - fh® c h a r a c t e r i s t i c i l t h o l o g y o f th© Z i Ip ha s h a le may bo e©®® a t th© exposure h e r e i n e e lo o te d a s th© ty p e l o c a l i t y which i e a lo n g t h e county road a t B ucksnort H i l l , one and a h a l f m i l e s n t r t h o f z i l p h a Creek and n e a r th® c e n t e r o f s e c t i o n @/TL6 N/B6 SE» extrem e n o r th w e s te r n A t t a l a County, ^ i e a i e s i p p i *

The s e c t i o n her© i o i

ZILPHa SHABS - u p p e r c o n ta c t n o t exposed 29*

carb o n aceo u s s h a le - c h o c o l a t e brown to l i g h t g ray t o d a rk red* abundant p a r t i n g s o f l i g h t g ra y s i l t and many pocket® , s t r i n g e r s and i n t e r b e d e o f h ig h ly g l a u c o n i t i c m a t e r i a l o ccur t o w i t h in 4 f e e t o f th e tap} few t h i n s t r i n g e r s o f s o f t , whit©} giau«* e o n i t i e t i liste n © } p l a n t fra g m e n ts common i n th e c h o c o la te m a t © r i a l $ g r a d in g down i n t o

22 ^*

carbo naceou s s h a le - s i m i l a r to above but n o n - g l a u c c n i t i c j u p p e r 14* b a d ly w eath ered and slumped} g r a d in g down i n t o

2 ^-'

g l a u c o n i t i c sandy c la y * c h o c o la te t o l i g h t g r a y ; g l a u c o n i t e a n a q u a r t s sand c o n c e n tr a te d i n p o c k e ts and s t r i n g e r s n e a r base and becoming r a r e tow ard t c p ; few t h i n , i r r e g u l a r c o n c r e t i o n a r y led g e s o f l i m o n i t i c c l a y e t o n e 5 s c a t t e r e d molds o f fo s s il© } t h i s bed i s r e a l l y th e t r a n s i t i o n s e c t i o n between t y p i c a l Zi ip ha and

Inotta f a c i e s

C o n ta c t conform able 54*

T o ta l t h i c k n e s s o f

i I p h a exposed

•/IWOSA GRSShSAMD 4*

heavy c o n c r e tio n a r y ledge o f l im o n i ti o san d sto n e developed on we&iherea greeneand} meet prom inent bed i n s e c t i o n

32

10*

f c e s i l i f e r o u e green eand * l i g h t g r e e n i s h g ra y t o yellow -brow n t o dark* b r io k r e d ; m assiv e t© i r r e g u l a r l y bedded; f o e e i l a a b u n d an t a s laclcls e o ncentr& ted in e m a il l e n s e s ; u p p e r 4 t o 8 f e e t o f t h i s s e c t i o n very i t 'r e g u l a r l y i n d u r a t e d ; d i s o r i e n t e d

p e l l e t s * t u b e s ana i n c l u s i o n s o f g ray c la y common; much o f g l a u c o n i t e o f c o a rse eand s i r e ; g ra d in g down i n t o 5*

g l a u c o n i t i c sand o r groeneand - s i m i l a r to above but l o s s g l a u c o n i t i c and l e s s i o s s i l i f a r c u s c arb onaceou s c la y - ohogo l a t e to g r a y ; sandy and honeycombed w ith s a n d - f i l l e d boring® and p o c k e t s ; p in c h e s o u t i n c u t

6 j*

g l a u c o n i t i c sand o r gro eneand - l i g h t g r e e n i s h gray to yellow -brow n and r e d ; u p p e r h a l f th in -b e d d e d and banded; lower h a l f c o n t a i n s a s abundance o f d i s o r i e n t e d p e l l e t s and f i l l e d t u b e s o f g ra y c l a y ; beds i - r e g u l a r l y s t a i n e d b la c k by manganese © x id e (l)

35*

T o ta l t h i c k n e s s o f

in o n a exposed

Base of s e c t i o n a t £ lo o d p la in l e v e l of Big Black R iv e r ~ E l e v a t i o n 285 ( a l t i m e t e r ) T o ta l s e c t i o n exposed - 80* ■i& i n d i c a t e d by t h e d e s c r ib e d s e c tio n * th© £ilpb& fo rm a tio n i e composed c h i e f l y o f carbonaceous s h a l e and clay*

hen f r e s h * t h i s

m a t e r i a l i s b l a c k , but i t i s r e a d i l y o x i d iz e d to a c h o c o la te brown o r gray c o l o r and i s u s u a l l y seen on th e s u r f a c e in t h a t c o n d itio n * I t u l t i m a t e l y w e ath e rs t o a d a rk , b r i c k r e d c la y .

*lhe lower p a r t o f

t h e e e e t i e n i s t y p i c a l l y a n e a r l y - p u r e , blocky c l a y , w hile th e upper p o r t i o n i e much more s i l t y and s h a l y .

a r t i n g e , s t r i n g e r s and le n s e s

o f m icaceous e i i i and sa n d , many o f which e x h i b i t high a n g le c r o s s - b e d -

d i n g , a r e t h e most common a s s o c ia te ® o f t h e oboco l a t e s h a le s #

.; l e n t

fr a g m e n ts a r e found through® at t h e s e c t i o n , b u t t e n d to be much more ab u n d an t i n t h e u p p e r , sh a iy f a c i e s # The lew ®m ost few f e e t o f the :iipfaa a r e g l a u c o n i t i c and sa n d y , thee® tw® m a te ria l® b e in g abundant and i r r e g u l a r l y d i s t r i b u t e d n e a r th e b a a a l c o n ta c t a n d becoming i n c r e a s i n g l y r a r e above*

Gla u -

c o n i t e ale® o c c u rs i n sm a ll le n s e s and p o c k e te which a r e found a l l t h e way to t h e to p o f t h e fo rm atio n *

In n o r th w e s te r n

t t a l a County

where t h e C ilp h a r e a c h e s it® maximum d ev elo p m en t, th® s h a l e s o f t h e upp er p a r t o f th® s e c t i o n a r e o f t e n h ig h ly g l a u c o n i t i c *

several

g l a u c o n i t i c bed® can be re c o g n is e d a t some outcrop® i n t h a t are a* Throughout t h e s o u t h e a s t e r n p a r t o f th e z i i p b a o u tc r o p t h e r e i® a d ie c o n tin u o u s groenean d bed a t t h e top o f t h e fo rm atio n*

it is

a d a rk g r e e n i s h g r a y , f i n e g r a i n e d , a r g i l l a c e o u s , l i g n i t i c groeneand which i® s p a r i n g l y f o e e i l i f e r o u e a t a few l o c a l i t i e s #

I t reach®® a

maximum t h i c k n e s s o f 15 f e e t i n th® a r e a w est o f Union, Newton County# T h is g re e n sa n d i e s e p a r a t e d from th® o v e r l y i n g b a s a l Kosciusko sand by a few f e e t &i s p a r i n g l y g l a u c o n i t i c t i l t *

i n s o u th e r n Neshoba

County t h e r e a r e s e v e r a l le n s e s o f g l a u c o n i t i c sand and g reen san d which l i e from 20 t o 30 f e e t above th e main body o f t h e lil p h a * Thee® le n s e s were sa p p ed a s p a r t o f th e k i lp b a i n o r d e r to i n c lu d e a s much m arin e m a t e r i a l a s p o s s i b l e i n t h a t fo rm a tio n r a t h e r th a n In t h e nen*>marin& K osciusko form atio n# 601 &&

of t h e c o n c r e t i o n s formed in t h e z ilp im a r e very u s e f u l

i n i d e n t i f y i n g th e deeply w eath ered outcrop*

-y f a r th e most abuna&nt

t y p e found i s a s o f t , f l a k y , yellow-brown U m o n itic s i I t s t o n ® which i e formed a lo n g t h e e i l t y p a r t i n g s o f t h e s h a le by t h e d e p o s i t i o n o f

34 i r o n o x id e from c i r c u l a t i n g g r o u n d w a t e r •

a

s i m i l a r ty p o o f c l a y s t o n e

o f t e n form® a s lod g es o f d e n s e , h a rd m a t e r i a l a t th© to p o f th e s h a l e se c tio n .

l a t h e n o r t h e r n and s o u t h e a s t e r n p a r t s o f th© a r e a mapped

t h e s e le d g e s a r e s t r o n g and p e r s i s t e n t and s e r v e a© good m ark ers f o r t h e top o f th e form atio n* Throughout n o r t h - c e n t r a l A t t a l a County, where th© z i ipha i s b e s t d e v e lo p e d , ro u n d ed , yellow -brow n lim c m itic e la y a to n e o r i r o n s t o n e c o n c r e t i o n s a r e commonly found*

These c o n c r e t i o n s a r e hollow o r spongy

i n t h e i n t e r i o r and have a c h a r a c t e r i s t i c s h e l l y o r c o n c e n tr i c s t r u c t u r e * They o c c u r a t d e f i n i t e h o riz o n s a s weak ledge® and a r e d e r i v e d from w e a th e re d s i d e r i t e * Lower C o n tact - The 2 i l p b a - ia o n a c o n t a c t I s conform able and s h a r p l y d e fin e d *

The m a t e r i a l a t t h e c o n ta c t p r o p e r 1 © a h e te r o g e -

bogus m ix tu re o f carbonaceous c l a y , g l a u c o n i t e and q u a r t s sand*

Below

t h i s taerison t h e c la y d i m i n i s h e s and d isa p p e a r® , w h ile above i t th e g l a u c o n i t e and q u a r t s sand g r a d u a l l y do lik e w ise *

The a c t u a l t r a n ­

s i t i o n from one fa c ie ® t o t h e o t h e r o c c u rs w ith in ^ to 3 f e e t o f s e c t i o n e x c e p t in a few p l a c e s i n

. t t a l a County where t h e two f a c i e s

a r e fau n a in te r b e d d e d a t th e c o n ta c t*

The l i t b o logy o f th e o v e r l y i n g

and u n d e r l y i n g beds and t h e s h a r p n e s s o f th e c o n ta c t I n d i c a t e t h a t t h i s c o n ta c t r e p r e s e n t s a r a p i d change from shallo w m arine to m arsh c o n d itio n s *

The h e t e r o g e n e i t y o f th e m a t e r i a l a t t h e c o n ta c t was

p r o b a b ly caused by wave a g i t a t i o n d u rin g t h e change o f c o n d itio n s * T h is c o n ta c t i s t h e s h a r p e s t and most r e l i a b l e one In th e C la ib o r n e s e c t i o n i n M i s s i s s i p p i and i t i s th e only one which p e r s i s t s a c r o s s t h e s t a t e w ith o u t e x te n s iv e f a c i e s changes*

Lor t h e s e r e a s o n s

i t was u se d a s t h e datum p la n e upon which i l a t e % was c o n s tru c te d *

35 T h ic k n e ss - The t h i c k n e s s o f t h e Zi ipha s h a l e r a n g e s from Q to ?5 f e e t i n M i s s i s s i p p i and v a r i e s w id e ly o v e r s h o r t d i s t a n c e s a s shown on I l a t e 2*

The fo rm a tio n i e t h i n and a b s e n t a t a few l o c a l i t i e s i n

C la rk e and L a u d e rd a le c o u n tie s * a v e r a g in g a b o u t IS f e e t and ra n g in g up t o 35 f e e t i n t h i e k n e e s i n t h a t are a*

I t becomes t h i c k e r th ro u g h

t h e c e n t r a l p a r t o f i t s o u tc ro p * a v e r a g in g about 25 f e e t and ra n g in g ficm C to dQ f e e t and b e in g a b s e n t a t a few l o c a l i t i e s i n e a s t e r n Leake County*

The maximum development i s rea ch e d i n A t t a l a and Holmes

C o u n tie s where th e a v e ra g e t h i c k n e s s i s a o o u t 40 f e e t and t h e maximum o f 15 f e e t i e a t t a i n e d *

N orth o f t h a t a r e a t h e a v e ra g e t h i c k n e s s

d e c r e a s e s to a b o u t 15 f e e t and t h e r e a r e numerous l o c a l i t i e s where t h e fo rm a tio n i s t h i n t o a b sen t* Hog s i I s - I n p l a c e s where the Z ilp h a o v e r l i e s i o e s i l i i 'e r o u s Winona m a t e r i a l * t h e b a s a l few f e e t of t h e s h a le u s u a l l y c o n ta in f o s s i l molds* but f r e s h f o s s i l s a r e v e ry r a r e i n th e fo rm ation* O at£ea a a l l a e f p r a i e n r .

Both

lls b g a s sg A s U 1 t ro e cut g l i a m lg g j j s i p p t e n Ble

o c c u r i s t h i s b a s a l p a r t o f t h e form ation*

N e i t h e r th e m acrofauna

n o r t h e m ic ro fa u n a of t h e Z iIp ha have been s t u d i e d i n d e t a i l * l i s t r i b u t t o n » Th© sm a ll s c a l e o f t h e g e o l o g i c a l map p r e c l u d e s showing b e t s th e Z ilp h a and Linona o u tc ro p b e l t s and so th e y a r e com­ bined*

The r e l a t i v e a r e a l d i s t r i b u t i o n o f th e two f o r m a tio n s can be

o b ta in e d by a stu d y o f Figure® 1 and 2 t o g e th e r * Z ilp h a and

The o utcrop o f th e

in c n a fo rm a tio n s i n e a s t e r n M i s s i s s i p p i i© a t h i n and very

i r r e g u l a r b e l t which f o llo w s t h e T a l l a h a t t a o u tc ro p c l o s e l y and has b u t a few to p o g r a p h ic o u t l i e r s and i n l i e r s *

I n th e c e n t r a l p a r t o f th e

a r e a t h i s b e l t expands to an a v e ra g e w idth of a b o u t two m ile s ana i t s

36 i r r e g u l a r i t y and th e numerous to p o g ra p h ic o u t l i e r s r e f l e c t t h e e t r e n g i h of th e

in o n a Cuaata*

Jm n o r t h e a s t e r n C a r r o l l , n o r t h e r n Montgomery aad

G renada C o u n tie s t h e o u tc ro p i e an i r r e g u l a r h o l t a v e r a g in g a b o u t h a l f a m il e i n w id th and having s e v e r a l to p o g ra p h ic o u t l i e r # and 2 n t i e r s # ■i$Jk9SF9V.W* aypreaB iP E - xb« Hi iph a s h a le has a weak top©—

g r a p h i c e x p re s s io n #

The o u tc ro p i s u s u a l ly marked by a to p o g r a p h ic

f l a t o r beach which i e o f t e n o f c o n s i d e r a b le a i d i e mapping o p e ra tio n s # ^oil© - The Z ilp h a s h a le g iv e s r i s e to a gray o r brownish g r a y , very f i n e candy loam c o il#

The t o p - s o i l ra n g e s up to 6 in c h e s i n

t h i c k n e s s and t h e s u b - s o i l i s o f from 14 to £Q in c h e s o f brown to r e d , heav y , p l a s t i c s i l t y c la y o r clay#

The s u b - s o i l i s u s u a l l y

u n d e r l a i n by a m o tt l e d gray and r e d , heav y , p l a s t i c c la y and i n p l a c e s t h e t o p - s o i l r e s t s d i r e c t l y upon t h i s m a t e r i a l #

These c o i l s

a r e known a s t h e B osw ell Oi buaquehanna o r some c l o s e l y a l l i e d s e r i e s * They a r e d i s t i n c t i v e and of c o n s i d e r a b le help i n m apping, brut a r e g e n e r a l l y re g a rd e d a s poor a g r i c u l t u r a l s o i l s * ^ o e i t i o a a l C o n d i ti o n s - The n a t u r e o f th© o v e r l y i n g and u n d e r l y i n g m a t e r i a l s i n d i c a t e s t h a t th e Z i ipha s h a l e was d e p o s i t e d c u r i n g a time o f change from marine t o hen-marin© c o n d i t i o n s * f o r m a t i o n has t h e c h a r a c t e r i s t i c ; - o f both t y p e s o f d e p o s i t s # l i t h e logy s u g g e s t s t h a t , f o l l o w i n g t h e d e p o s i t i o n of th e

The its

i n o n a , th©

s h o r e l i n e r e f l o a t e d i n th© lac© of a c c e l e r a t e d non-marine sedim enta ­ tion*

Tbe f i r s t i n d i c a t i o n o f a change in c o n d i t i o n s i s t h e a p p e a r ­

an ce of ©lay which was a p p a r e n t l y d e p o s i t e d in very shallo w w a t e r where wave a c t i o n mixed i t t h o r o u g h ly w i t h th© u n d e r l y i n g greensande* r»e t h e sh o re Ain© r e t r e a t e d f a r t h e r seaw ard, t h i s cla y was covered by s i l t y c l a y s , s i l t s and sands d e p o e l t e a on t h e t i d a l f l a t s and i n

t h e c o a s t a l marsh*

The h i g h a n g l e c r e s s - b e d d i n g i n t h e s i l t l u t e r h e a a

i n t h e upper* a h o i ; p o r t i o n e l t h e z i ip ha i n d i c a t e s depoei t io n & l con-* c ii t io n e i n which c u r r e n t a p l a y e d an im p o rta n t p a r t *

The p r o b a b le s i t e

ox d e p o s i t i o n o f t h i s mat © r i a l was i n lake© and bays i n t h e c o a s t a l marsh where t h e waves and b e t t o r c u r r e n t © winnowed t h e s ills ? ou t o f t h e mar eh d e p o s i t s * The greens&nd bed a t th e to p o f t h e &ilph& i n e a s t e r n a l e e i e s i p p i , t h e g l a u c o n i t i c eand le n s e s above t h e main body o f th e b i l p h a i n s o u th e rn Neshoba County and t h e s e v e r a l g l a u c o n i t i c beds i n t h e f o r m a tio n i n a t t a i n County were a l l a p p a r e n t l y d e p o s ite d d u r in g l o c a l , m in e r a d v an ces o f th e sea* The c o n ta c t r e l a t i o n s h i p s i n d i c a t e t h a t t h e ab sence of t h e bilpha. s h a le a t & few l o c a l i t i e s i n th e s t a t e i s due t o sim ple n o n - d e p o s i ti o n o f t h e f a c i e s r a t h e r th a n urecnform&fol© o v e rla p * The t h i n n e s s o f t h e lower t r a n s i t i o n f a c i e s * r a r i t y o f a r e p e t i t i o n o f f a c i e s a t t h e c o n ta c t and t h e g e n e r a l t h i n n e s s o f t h e b l i p h a s e c t i o n a c r o s s t h e s t a t e i n d i c a t e t h a t th e change from m arine t o non-m arine c o n d i t i o n s o c c u r r e d r a p i d l y o v e r a wide area*

38 f 0 S C I O S KG FO R M A TIO N

I n t r o d u c t i o n - t b e t e r n Kosciusko m e p ro p o se d by Cook® ( 1 4 ) t o r e p l a c e Lowe*s ter® °Decatur«* which m e p reo c cu p ie d *

Cooke*e

o r i g i n a l d e f i n i t i o n o f t h e Kosciusko is* “The same Kosciusko sa n d sto n e member i e h e re pro p o sed a s a d e s i g n a t i o n f o r t h e le&gea o f s& c e h a ro id a l to q u a r t e t t i c s a n d sto n e e x posed i n t h e v i c i n i t y o f K o sciu sk o , th e county s e a t o f A t t a i n C ounty, M i s s i s s i p p i , and f o r th e u n c o n s o lid a te d sand s o f th e same a g e i n M ississippi*** The beds s p e c i f i e d by Cooke l i e n e a r t h e b a s e o f a t h i c k s e c t i o n o f non-m arine sa n ds and s h a l e s which cannot be s a t i s f a c t o r i l y s u b d iv id e d and so t h e term K osciusko i s r e d e f i n e d i n t h i s r e p o r t t o i n c l u d e a l l beds above th e L ilp h a s h a l e and below th e

a u tu b b e e

f o r m a t io n , Most w ork ers s i n c e Cooke have c o n s id e re d t h e Kosciusko t o be a member o f t h e L isbon f o r m a t io n .

I t i s h e r e i n r a i s e d to t h e

ran k o f a fo rm a tio n b ecause i t i e a l i t h o i o g i c u n i t w ith d e f i n a b l e u p p e r and low er b o u n d a rie s which has a wide a r e a l d i s t r i b u t i o n * L ith e logy ~ The Kosciusko fo rm a tio n i s a h e te r o g e n e o u s , h ig h ly l e n t i c u l a r , n on-m arine s e c t i o n i n which sands and s h a l e s a r e t h e dom inant f a c i e s *

The b a e a l 50 to 200 f e e t o f th e f o rm a tio n i s

t y p i c a l l y composed o f m assiv e to h ig h ly oro se -b ed a ed sands which a r e c o lo r e d r e d , brow*., y e llo w , p u r p l e , p i n k , v i o l e t , gray and w h ite on t h e outcrop*

T his v i v id c o l o r a t i o n i s a s u r f a c e e f f e c t ,

s i n c e t h e sands a r e i n v a r i a b l y l i g h t c o lo r e d i n w e ll samples*

These

sam ples a l s o show t h a t some o f th e sands a r e s p a r i n g ly l i g n i t i c .

The

sand s a r e p red o m in a n tly f i n e g r a in e d and f a i r l y w e ll s o r t e d , b u t ex* ( 1 4 ) C. yyths Cooke9 ojo. p i t * , pp* 135-136*

3® h i b i t a i l v a r ia tio n ® i n g r a i n e l s e and d e g re e o f s o r t i n g .

The i n ­

d i v i d u a l g r a i n s a r e u s u a l l y c o a te d w ith a t h i n f i l m o f i r o n o x i d e . Clay o c c u r s i n t h e ©and a s p e l l e t s , h a l l s , i r r e g u l a r i n c l u ­ s i o n s , p a r t i n g s and s t r i n g e r s *

I n a few p l a c e s t h e s e in c lu sio n ®

become a b u n d an t enough t o form e la y - b & li conglom erates*

The c la y

i s a l i g h t g r a y , sandy o r s i l t y m a t e r i a l which becomes m o ttle d p in k o r p u r p l e when s l i g h t l y w eathered* S h a le s i n c r e a s e i n abundance above th e b a s a l sand u n t i l th e y u s u a l l y p red o m in ate o ver t h e sand i n t h e u p p e r p a r t o f th e s e c tio n * There a r e t h r e e t y p e s o f s h a le i n t h e Kosciusko*

The l i g h t gray to

m o t t l e d p u r p l e and g r a y , s i l t y c la y which i s found a s s t r in g e r ® and p e l l e t © i n t h e sa n d s a l s o o c c u r a s le n s e s o f s h a l e d i s t r i b u t e d th r o u g h o u t th e fo r m a tio n .

Black to c h o c o la te brown, c arb onaceo us

s h a l e s i d e n t i c a l t o th e carbonaceous s h a l e s o f th e M lp h n and o t h e r C la ib o rn e f o r m a tio n s a r e common a s l e n s e s i n th e Koeciusko th ro u g h o u t t h e c e n t r a l and w e s te r n p a r t o f i t s o u t c r o p . d a rk g ray t o g r e e n i s h gray

The t h i r d typo i s a

f r e s h ) t o l i g h t gray o r brow nish g ray

( w e a t h e r e d ) , i i g n i t i c , s i l t y s h a le which g ra d e s i n t o th e carbonaceous s h a l e s on one h ard and i n t o a r g i l l a c e o u s s i l t s on t h e o t h e r .

These

s i l t y s h a l e s vary in s t r u c t u r e f r o ® even-bedded and la m in a te d to h ig h ly cross-bed ded*

I l e n t fra g m e n ts a r e abundant and w e ll p r e s e r v e d

f o s s i l le a v e s a r e found a t a few l o c a l i t i e s .

le a th e r e d rem ains o f

s i a e r i l e concretion® up to one f o o t l a r g e s t d ia m e te r a r e q u i t e common* These s h a l e s a r e p a r t i c u l a r l y abundant i n th e Kosciusko i n C a r r o l l County and a r e w e ll exposed a lo n g th e highway between Tinona and C a r r o l l to n * The le d g e s of q u a r t s i t i c sa n d sto n e m entioned by Cooke i n

40 h i s o r i g i n a l a e i i n i t r o n of t h e Koeeiuek© a r e th e most d i s t i n c t i v e f e a t u r e o f t h s fo rm atio n *

They airs l i g h t g r a y , s i l i c e o u s * c o a rse

s i I t s t o n e s which form by s u r f a c e i n d u r a t i o n from l i g h t gray* compact* a r g i l l a c e o u s s i l t l e n s e s i n t h e m assiv e Kosciusko sa n d s and which a p p e a r on t h e o u tc ro p a s q u a r t s ! t i c b o u ld e r s and ledges*

They a r e

b e s t d e v elo p ed i n a t t a i n and Holmes C o u n tie s where th e y form d i^ c o n ­ t i n u o u s led g e s which occupy a e t r a t i g r a p h t c h o r i s e n SO to 7& f e e t above t h e to p o f t h e Zilpha*

They a l e e o c c u r in Grenada* C a r r o l l ,

Me&ke and denhoba C o u n tie s , but th ey a r e only l o c a l l y develo ped i n t h o s e c o u n tie s *

Meet o f th e o l d e r a u th o r s m istook t h e s e led g e s i n

A t t a l a and Holmes C o u n tie s f o r i a l l a b a t t a m a t e r i a l and c o n s id e r e d t h e C la ib o rn e s e c t i o n below them t o be o f l a l l a h a t t a age*

Cooke

( IS) was f i r s t t o re c o g n iz e t h e i r t r u e s t r a t i g r a m h i e p o s i t i o n * i e t r i f i e d wood and l i g n i t e a r e very r a r e i n t h e Kosciusko fo rela tio n which sometimes s e r v e s t o d i f f e r e n t i a t e t h e fo rm a tio n from i l c c j t and C o c k f ie ia beds*

ale e ,

th e sands o f th e Kosciusko a r e

r a r e l y m ic ac eo u s, a f a c t which h e lp s t o d i f f e r e n t i a t e them from t h s low er C la ib o rn e sands* i m o n i t i c s a n d s to n e , s i I t s t o n e and c la y s to n e a r e th e common c o n c r e t i o n a r y m a t e r i a l s o c c u r r i n g i n t h e Kosciusko* c h a r a c t e r i s t i c l i t h e l e g y and p la c e of occu rren ce*

each has i t s -11 a r e produced

by t h e d e p o s i t i o n o f lim o n ite by c i r c u l a t i n g g ro u n d -w a te r and a r e s u r f a c e phenomena*

^ im o n itic s a n d sto n e forma as i r r e g u l a r led g es

o r i n c l u s i o n s i n t h e i r o n - s t a i n e d sands* f l u te d o r tu b u la r stru c tu re * ( IS) ib id .* f F* 1 3 b*

I t o c c a s i o n a l l y has a

i t v a r i e s from yellow -brow n and sorae-

41 w hat i n d u r a t e d t o d a rk brawn and v a ry hard*

Lomelimes t h e s e b o d ie s

f o r a on t o p o f s l a y s t r i n g e r s where g ro u n d -w a te r c i r c u l a t i o n ha® been impeded*

E lsew here th e y form i s m assiv e sa nd s where t h e r e i s no

a p p a r e n t r e a s o n f o r t h e i r lo c a tio n *

T h is r o a t e r i a l i e abundant

th r o u g h o u t th e Kosciusko and a i l s i m i l a r sands i n t h e C la ib o rn e i n • ise is sip p i.

T is a e n itie s i l i s t e n s o c c u r s a s f l a k y » yellow -brow n con­

c r e t i o n s which form a lo n g t h e s i l t y p a r t i n g s i n t h e s h a l e s o f t h e Kosciusko and eh aly f a c i e s o f o t h e r fo rm a tio n s* i e t h e l e a s t a bu ndan t o f th e t h r e e ty p es#

Limoni t i c c lay e to n e

I t o c c u rs r a r e l y a t th e

to p o f c h o c o la te brown s h a l e le n e e s i n t h e form ation*

The e id © rite

c o n c r e t i o n s i n t h e s i l t y s h a l e s w e ath e r to s h e l l y o r c o n c e n t r i c - s t r u c ­ t u r e d l i r a o n i t i e c la y s t o n e o r i r o n s t o n e bodies* -ower c o n ta c t - The £ © s e i u e k o - £ i l |h a c o n ta c t i s conform able and g r a d a t i o n a l *

The g r a d a t io n o c cu rs from t h e b a s a l Kosciusko sand

th ro u g h an i n te r b e d d e d sand and s h a l e s e c t i o n i n t o th e t y p i c a l Z ilp h a sh a le*

The t h i c k n e s s of th e t r a n s i t i o n s e c t i o n v a r i e s from a few

i n c h e s t o 30 f e e t and o f t e n changee q u i t e m arkedly o v e r s h o r t d i s ­ ta n c e s *

I n e a s t e r n M i s s i s s i p p i where th e to p o f th e T iipha i s marked

by a g re e n sa n d bed th e t r a n s i t i o n t a k e s p la c e th ro u g h a t h i n s e c t i o n o f s p a r i n g ly g l a u c o n i t i c s i l t a n a a s i m i l a r s i t u a t i o n exist® i n th e few p l a c e s where th e yoeciusfco l i e s d i r e c t l y upon th e

inona g re e n sa n d .

T h ic k n ess - The t h i c k n e s s o f th e Kosciusko fo rm a tio n g r a d u a l ly i n c r e a s e s n orthw estw ard a lo n g th e s t r i k e from &5 f e e t a t t h e

.labama

l i n e t o a maximum o f 400 f e e t in A tt a l a * Holmes and C a r r o l l Counties* The t h i c k n e s s e s In t h e e a s t e r n p a r t o f th e s t a t e were measured d i r e c t l y ©n t h e o u tcro p * thoe©

lu

th e c e n t r a l p a r t a r e d e riv e d from p r o f i l e s *

and th o s e in t h e w estern p a r t a b i K u p o n /"v B

UEittftfW

p r o j e c t i o n s of s u r f a c e



d i p s combined w ith w a te r and o i l w e ll d a ta * F o e g i le » f o s s i l le a v e s a r e found i n th e s i l t y s h a l e s i n C a r r o l l County*

The f l o r a has n o t been stu d ied #

D i s t r i b u t i o n - i n e a s t e r n C lark e County t h e Kosciusko o u tc r o p forma an i r r e g u l a r b e l t a v e r a g in g a b o u t 6 m ile s I n width*

N orthw est*

ward a c r o s s t h e s t a t e t h i s b e l t i n c r e a s e s i n w idth to a maximum o f 2 0 s t i l e s i n a t t a i n and Holmes Counties*

D e t a i l s of th e d i s t r i b u t i o n

o f t h e f o r m a tio n a r e shewn on F l a t s 1. T opographic S x o ro s e io n * t h e b a s a l sands e f t h e Kosciusko su p p o r t a c o m p a ra tiv e ly rugged sand h i l l s topography*

In easte rn

M i s s i s s i p p i t h i s sand h i l l s topography i s superim posed upon t h e g e n t l e s lo p e o f th e S u h r s te n s C uesta and th r o u g h o u t th e rem ainder o f t h e a r e a mapped i t i e superim posed upon t h e g e n t l e s lo p e o f th e c u e s t a d e v elo p ed on th e Winona*

i n t h e a r e a s where th e 2;ilpha

f o r m a tio n i s w e ll d ev elo p ed t h e s e sands form an escarpm ent o v e r ­ lo ok in g t h e to p o g ra p h ic f l a t developed on th e o u tc r o p o f th e sh a le* The a v e r a g e l o c a l r e l i e f i n th e sand h i l l s i s a b o u t 7S f e e t , w hile t h e maximum i e a b o u t 15'- f e e t *

The u p p e r, more ehaiy p o r t i o n o f

t h e fo r m a tio n s u p p o r ts a more r o l l i n g ty p e o f topography i n which t h e l o c a l r e l i e f a v e ra g e s ab o u t 50 f e e t * The q u a r t s i t i c s i I t s t o n e ledges in t h e

o sc iu sk o i n A t t a l a

and Holmes c o u n t i e s e x e r t a s t r o n g i n f l u e n c e upon th e topography* They s u p p o rt a b o ld escarpm ent a lo n g which th e most rugged tepog* ra p by i n t h e Kosciueko o u tcro p b e l t i e found* c o i l s - The sa n ds o f th e Kosciusko g iv e r i s e t o f i n e candy loam and fin© eand s o i l s known a s B o sto n, G r e e n v ille * Orangeburg

43

o r N e r f o lk o r some c l o s e l y a l l i e d s e r i e s *

They have been d e s c r i b e d

u n d e r t h e s o i l s o f t h e Leshoba sand os page 2 £« The sand and s h a l e s e c t i o n s o f th e *c e c iu e k o g iv e r i s e to a s i m i l a r f i n e sandy loam which has more c la y i n t h e e u b - e o i l .

T his

i s t h e Shubuta f i n e sandy loam o r some c l o s e l y a l l i e d type* i n e a s t e r n :.i Ip h a -ty p e carbonaceous s h a le le n s e s th ro u g h t h e s e c t i o n i n d i c a t e s c o n d it i o n s not g r e a t l y d i f f e r e n t from th e marshy c o n d itio n s a t o r n e a r s e a - l e v e l un der which th e Z ilp h a was d e p o site d *

in ly

a lo n g a s u b s id in g c o a s t l i n e could a s much a s 400 f e e t of such n e a r - s e a - l e v e l m a te r ia ls be d e p o site d *

44 The i i t h o i o g y o f th© ^ o ec iu sko suggest© t h a t , fcimowing t h e d e p o s i t i o n o f th© z i lpha> t b e c o a s t a l marsh was f l o o d e d by stream-born© sa nd s w h ile t h e f i n e r g r a i n e d m a t e r i a l © were c a r r i e d f a r t h e r out and d e p o s i t e d i n t h e c o a s t a l marsh o r i n c o r p o r a t e d i s t h e marine deposit©* The g e n e r a l t h i n n e s s o f t h e t r a n s i t i o n f a o i s e between t h e ^ i l p h a and i o s c i u e k c formation© i n d i c a t e s t h a t t h i s change o c c u r r e d r a p i d l y * j u r i n g m id d le *ad u p per Kosciusko time t h e g r a d ie n t© of t h e stream s on t h e d e l t a i c p l a i n were d i m i n i s h e d and much of th e f i n e r g r a i n e d m a t e r i a l s a s croppe d on t h e c o a s t a l p l a i n where i t now a p p e a r s a s s i l t s and s h a l e s * There i s l i t t l e p o s i t i v e evidence r e g a r d i n g t h e condition® Uf: . e r which t h e q u a r t s i t i e s i listen©© of t h e Kosciusko were d e p o site d * They a r e d e r i v e d from lease® of s i l t which a r e o v e r l a i n and u n d e r l a i n by f i n e - g r a i n e a , non-m arine sands*

mifhough t h e ledge© a r e d i s c o n ­

t i n u o u s , t h e i r main envelopment occur® a t ab ou t t h e same s t r a t i g r a p h i c horizon.

The f a c t s t h a t t h e y a r i s e from a d i s t i n c t i v e t y p e o f compact

s i l t and t h a t th e o v e r l y i n g and u n d e r l y i n g m a t e r i a l® a r e not s i l i c l f i e d s u g g e s t th&t t h e s i l i c e o u s cement may b© primary*

h p o s s i b l e ©it© o f

d e p o s i t i o n f o r t h e s e beds i e i n ire© h-#at© r lake® on t h e u e l t a i c p l a i n i n which email q u a n t i t i e s o f o pa l were be in g p r e c i p i t a t e d *

45 ■aUTUBBEE FOBMAEtGN m ssM & U m Th» t e n s .au tu b b .a w*a in trod u ced by toaa in 19 IS ( 1 6 ) ! tba name b ein g tak en t r a m Tautucbee b t a t i o n on t h e so u th ern H a iiroa d i n

n o r t h w e s t e r n C larke county*

The o r i g i n a l d e f i n i t i o n l e t

11The autubbee Lari® c o n s t i t u t e th e m e t e x t e n s i v e d i v i s i o n o f th e L is b o n , s i n c e o t h e r member* o f th e form atio n have unimportant ou tcro p s* ‘he Vautubbee beds a r e a l l m a rin e , c o n s i s t i n g o f h ig h ly c a lc a r e o u s and f o s s i i i f e r o u s marl©, o f gray to alm ost w h ite c o l o r , o r o f d ark er b l u i s h and g r e e n is h t i n t s , due to th e p r e s e n c e o f g la u ­ c o n i t e . i n t b s v i c i n i t y o f liewten and a few o t h e r l o c a l i t i e s t h e s e m arie p a s s v e r t i c a l l y i n t o c l a y s or sands which a r e o f t e n l i g n i t i c and f o s e i l i f e r o u s * The Wautubbee m arls a r e l o c a l l y r ic h i n marine f o s s i l s , ex ­ h i b i t i n g a very c h a r a c t e r i s t i c fauna* The la r g e aaadie—sn&pea o y s t e r , o e t r e a e e l l a e f o r m i e , i s e s p e c i a l l y abundant* i n e e e beds i n s o u t h e a s t M i s s i s s i p p i have a t h i c k n e s s o f about lUo f e e t , and dip southward a t a r a te o f £3 to 2b f e e t to th e m ile* The t h ic k n e s s in west .. i e e i a s i p p i i s perhaps a s g r o a t , though not so evident*** g in e e th e term

autubbee i s s a t i s f a c t o r i l y d e f in e d and i e

w e l l e e ta b L is h e a i n th e l i t e r a t u r e , i t i s used i n t h i s rep o rt i n p r e f e r e n c e t© "Lisbon", Lisbon m a r l” o r " t y p i c a l Lisbon** b e c a u s e , a lth o u g h t h e

autubbee s e c t i o n i n c l u d e s beds which a r e l i t h e l o g i c a l l y

and f a u n a l l y i d e n t i c a l w ith t h e Lisbon form ation a t i t s typ e l o c a l i t y , t h o s e beds c o n s t i t u t e a minor p a r t o f t h e s e c t i o n which has been c a l l e d i.ieboE fo rm a tio n i n n e a r ly a l l o f th e l a t e r M i s s i s s i p p i report© and i t would be c o n fu sin g to r e s t r i c t such u w e l l e s t a b l i s h e d term* ,he term o e c iu e k o and below th e C o c k fie ld in e a s t e r n and c e n t r a l

ise ie e ip p i

and i t s non-m arine e q u i v a l e n t , th e Lhipp’ s Creek s h a l e , i n western V16) 3* &* Lowe, " M i s s i s s i p p i , i t s O e c lo g y , Geography, . ui le and M in era l r e s o u r c e © ," Mige* Geo^* M iA* i i ( 1 9 1 9 ) , pp. 7b-76*

46 M ississip p i*

t b s upp er c o n ta c t i s p la c e d a t t b s top of t b s carbonaceous

s h a l e s e c t i o n o v e r l y i n g th© marl© ( {Jordon Creek s h a l e member o f t h i s r e p o r t ) r a t h e r th a n a t t h e to p o f t h e m a rls th e m se lv e s because t h e s e s h a l e s e x h i b i t many m arin e c h a r a c t e r ! s t i e s and l o g i c a l l y belong i n t h e m arin e s e c tio n * T o st w o rkers i n

i e s i e a i p p i have c o n sid e re d th e Tautubbee bode

t o be a member o f t h e L isbon fo rm atio n *

The ^autubbee i s c o n s id e r e d

t c be a f o r m a tio n by t h e a u th o r because i t can be s u b d iv id e d i n t o s e v e r a l l i t h o l o g i c u n i t s which a r e l o g i c a l l y members and because i t has a wide a r e a l d i s t r i b u t i o n * ^n e a s t e r n M i s s i s s i p p i t h e

a u tu b b e e s e c t i o n i s d i v i s i b l e i n t o

t h r e e d i s t i n c t i v e and p e r s i s t e n t l i t h o l o g i c u n i t s which a r e named and g iv e n t h e rank o f members i n t h i s r e p o r t* Gordon

They a r e :

reek ©hale member ( t o p )

F o t t e r c h i t t e member vrchusa m arl member ; bottom ) T his s u b a i v i s i o n becomes i m p r a c t i c a b l e i n c e n t r a l hewton County and th e fo rm a tio n i s mapped as u n d i f f e r e n t i a t e d

a u tu b b e e a s

f a r n o rth w e s t a s t h e Tockahockany L iv e r i n n o r th w e s te r n ^eake County* Beyoca t h a t p o i n t t h e s e c t i o n become© h ig h ly l e n t i c u l a r and i n so u th ­ w e ste rn - i t t a l a county th e m arine m a t e r i a l d isa p p e a rs* i n t e r f i n g e r i n g a lo n g t h e s t r i k e w ith non«*raarine beds*

i n w e ste rn Holme© and C a r r o l l

C o u n tie s t h e r e i s a t h i c k tongue of carbonaceous s h a le ly in g a t th e s t r a t i g r a p h i c b o ria e n of th e m arine

'autubbee*

i t i e named th e

chipp*© Creek s h a le member i n t h i s r e p o r t and i s c o n s id e re d t o be t h e non-m arine e x te n s io n oi th e } la te 2 * th e

Jautubbe© form ation*

- s shown on

au tu b b ee c o n ta c t s a r e a r b i t r a r i l y drawn a c r o s s t h e gap

47 betw een th© rorfc fewest erm aoet ex posure o f th© m arin e >:a u tu b b e e and t h e ty p e l o c a l i t y of t h e ohipp*e Creek sh ale* iirob usa

eJBEktt

i n t r o d u c t i o n * The name L rcbu ea i s ta k e n from Lrcfcusa s p r i n g e « a w ell-know n l o c a l i t y and form er h e a l t h r e s o r t on t h e Chickasawhay u i v©r s o u th o f t h e town o f ^uiim aa, C larke c o u n ty , ^ i e e i t e i p p i *

The

t y p e l o c a l i t y o f t h e member i e a b l u f f b e n e a th t h e so u th end o f t h e highway b r id g e and a c r o s s t h e r i v e r from t h e sp rin g e *

This member

h a s t h e same l i t h e logy a s th e Lisbon fo rm a tio n a t Lisbon ana C la ib o rn e b lu ffs,

ilabama*

..t c o n s t i t u t e s t h e m ajor p a r t o f Lowe's ‘?autubbe*

m arl and has been e a l l a u "C a lc a re o u s C la ib o rn e " by H ilg a rd and "Lisbon m arl* and " t y p i c a l .Lisbon" by o t h e r a u th o rs * ~ ith o logy - C h a r a c t e r i s t i c .*rehuea l i t ho Logy i e w e ll exposed a t t h e l o c a l i t y s e l e c t e d a s th e type* which i s a bluiC b e n e a th t h e s o u th ana o f t h e b r id g e a c r o s s t h e Chiekaaawb&y .T v e r on highway C* $* 45

two m il e s so u th o f ^uitman i n th e s z o f :;j$ o f s e c t i o n l4/T2H/r,153*

The s e c t i o n h ere s t a r t i n g one f o o t below road l e v e l a t an e l e v a t i o n o f ZZZ f a s t i s i ARCHIL’.'.-* ,.AKL it.SLbSii LF '^aUTUBB;5S £ OHMaTlCli — XKJPiS BSCTILK

m arl o r s o f t lim e sto n e - l i g h t gray t o w h ite , f o s s i U f ©roue, sandy and g l a u c o n i t i c 3f *

m arl - l i g h t g ra y to w h ite , f o s s i l i f e r o u e , eandy and s p a r i n g ly g l a u c o n it i c * ab uodam i r r e g u l a r ©lay i o e l u s i o n s * le e s i n d u r a t e d th a n bed above* s c a t t e r e d w eathered p y r i t i f e r e u e concretion®* abundant u s t r e a e e l la e f o r m i s and o t h e r f o s s il ® in b a s a l f o o t

ljj *

lim e sto n e - l i g h t g r a y , sandy, g l a u c o n i t i c and i o e e i l i f e r o u e * forms *ip of sm a ll f a l l s

48 a m ti - s i m i l a r to 3&* bed above* b e iy e a s e l l a e f o a r a i s and many

10 &*

o t h e r forme 1'

o y s te r bed - dark g reen , medium-grained greeise&nd w ith an abandonee o f O ctree se l laeform ie and comminuted she H e

8*

m arl - s im ila r to XQ$* bed above

1*

lim e s to n e - aiecontinuou© ledge o f m a t e r i a l s i m i l a r to t h a t

above

and below b u t s l i g h t l y more i n d u r a t e d 31*

m a rl - s i m i l a r to 1Q§' bed above Base ox s e c t i o n - low w a te r l e v e l o f Chiekasawhay i d v e r

46*

T o ta l t h i c k n e s s o f m easured s e c t i o n - n e i t h e r c o n ta c t exposed I n t h e a r e a a ro u n d GrandeIX i n e a s t e r n C larke County, th e

rch u e a becomes q u i t e l e n t i c u l a r and c o n ta in s b o d ie s o f n en -g l& u eo iaitie sandy b u t e ls e w h e re i t i s a p e r s i s t e n t , homogeneous u n i t*

on t h e

w e a th e re d o u tc ro p th e lim e i s lea ch e d from t h e sandy m a rls and th e r e s i d u a l m a t e r i a l i s a d ark r e d , s p a r i n g ly g l a u c o n i t i c sand w ith an abundance o f i r r e g u l a r c la y in c l u s i o n s *

hen d e ep ly w e a th e re d , th e

m arl c lo s e l y resem b les some o f t h e w eathered non-m arine C la ib o rn e sands* The b a s a l few f e e t of th e r.rehuea a r e t y p i c a l l y xuere sandy th a n th e rem aind er of t h e member*

T his p a r t of t h e s e c t i o n i e a f i n e

t o meaium g r a i n e d , s p a r i n g l y g l a u c o n i t i c , c a lc a r e o u s sand which i s r e la tiv e ly u n fo e e iiife ro u e .

Xt b e a rs t h e earns r e l a t i o n s h i p to th e

rchu aa a s th e p e b b l e - b e a r i n g , g l a u c o n i t i c sana a t th e base o f t h e b a s i c b e a r s to t h a t member*

The uppermost few f e e t of th© m a rl con­

t a i n a n g u la r frag m ents and i r r e g u l a r i n c l u s i o n s of ta n b e n t o n i t e a t a few l o c a l i t i e s i n Kewton County*

49 Bdwar C o n ta c t - Th® ./*r©teuea~Koeoiusko c o n ta c t i s d i s conform able and s h a r p l y d e fin e d *

i t c l o s e l y resem b les t h e B a s ie -M e rid ia n c o n ta c t

i n th© e a s t e r n M i s s i s s i p p i a r e a and u n do ubtedly r e p r e s e n t s th© same seq uence of events*

The t r a n s i t i o n frma maria© to non -m arine f a c i e s

o c c u r s w i t h ie a t t o 3 f o o t s e c t i o n i n which th© two f a c i e s a r e mixed i n a h e te ro g e n e o u s fa s h io n *

The b a s a l p o r t i o n o f th© Arcbusa c o n ta in s

s m a ll b lo c k s and i n c l u s i o n s of m a t e r i a l from th© beds bo low and sm a ll l e n s e s and p o c k e ts o f m a rl a r e found i n th e uppermost few f e e t o f th e Kosciusko*

M a r l - f i l i e d b o rin g s extend a f o o t ©r so down i n t o th©

non -m arine beds and -liegem inated glaucon.it© i s sometimes found a s much a© Xu f e e t below t h e co n ta ct* th e

The uppermost i ©eciusk© bade upon which

re h u s a r e s t s change l i t h o l o g y o v e r s h o r t d i s t a n c e s a long th©

s t r i k e from sa n ds t o carbon aceous s h a l e s to l i g n i t i c , g i l t y sh a les# T h is i e t h e c o n d itio n which would l o g i c a l l y be e x p ec te d a f t e r t r u n ­ c a t i o n o f t h e upperm ost beds of th e d e l t a i c pl&i*i by w a v e-e ro sio n a lo n g an a d v an c in g sh o re Line* I d s c o n ta c t i s & r e l i a b l e mapping fic u lt

horison., but i n

o ften d i f ­

to i d e n t i f y on t h e d eeply w eathered outcrop* T hickneae - The Arefcuea m a in ta in s a t h i c k n e s s o f 4£ to 60

f e e t in

lark©) J a s p e r and s o u t h e a s t e r r Kowton C o u n tie s .

I t Lens©©

out i n c e n t r a l Mawto o County, but r e a p p e a r s ®c a 15 f o o t len s i n n o rth ea stern

c e t t and n o r th w e s te r n bewton C o u n tie s .

To s a l I s * The eeljL aeform is sone of

d roh usa m arl c o n s titu te © p a r t of th e O c tre e ie a ia s ip p i# I t a lso

contain© a la r g e fauna

v e ry c l o s e l y r e l a t e d t o t h a t of th e m iu d le and upper Id ebon a t L is ­ bon and Ci&iboifle B l u f f s ,

Alabama*

to

i et-teretene

iffikyr

i n t r o d u c t i o n * t h e P o t t e r © h i t t o member i e named f o r an o u tc ro p s e a r l o t t e r c h i t t o Creek i n © o u th - c e n tr a l Newton County, ;..i© siaeippi* The ty p e © action i e exposed i n a e e r i e s of ro a d cut© a lo n g th e -©wtcn-^Qc&tur highway ( s t a t e Highway 15) on th© so u th v a l l e y w a ll o i t h e c re e k a b o u t 2 mile© n o r t h e a s t of t h e town o f Newton and i n t h e J*£ o f 26 and ss o f

©f £3/T6K /R il£ ( s e e p r o f i l e c,*

The member i©

l i t h o l o g i c a l l y t h e m ost h e te ro g e n e o u s o f th e t h r e e member© o f t h e a u tu b b e e fo rm a tio n o f e a s t e r n - i e s i s s i p p i , but c e r t a i n fe a tu re © make i t one of t h e moot e a s i l y i d e n t i f i e d on t h e w eath ered outorbp* ^ ith o lo a y

*

C h a r a c t e r i s t i c l i t h o logy o f th e

member i s w e ll exposed a t t h e ty p e l o c a l i t y *

i

O tte rc h itto

s t a r t i n g a t road l e v e l

a t th© to p of a h i l l o*o mile© n o r t h e a s t o f t h e J u n c t io n o f highway© U* b*

and s t a t e 15 a t an e l e v a t i o n o f 425, th e s e c t i o n exposed ie*

GOCttfISajj./ - Wuw-vTiQh 12*

©and w ith s h a le i n t e r c e d e - ©and red and red-brown* ©hale gray C o n tac t conform able and i r r e g u l a r l y ©lumped

AUltfBBSS fOni&illti.N GilSiSk GHitiiS -siSMBiSH 12*

carb onaceo us anal© to biocky clay - c h o c o la te brown to l i g h t y e llo w is h gray to r e d j b a s a l 2* eandy and g l a u c o n i t i c and h e te r o g e n e o u s | 2* above base i© a t h i n ledge o f whit©, s p a r ­ i n g ly g l a u c o n i t i c , s i l i c e o u s © iite to n e which i s a t y p i c a l f e a x u r e of th e member in t h i s a r e a c o n t a c t conform able

FCTlIiHCHiTXG tiJaiblSn - T¥r & ixfiiC'JTXUAl 6*

g l a u c o n i t i c sand - dark g r e e n i s h gray t o l i g h t g r e e n i s h gray to

red* a r g i l l a c e o u s and l i g n i t i c * i f o o t below top of tbi© bod i e & weakly develo ped c o n c r e t i o n a r y ledge w ith mold© o f fo ssil© * t e d l o c a l l y i n a u r a t e d i n t o s o f t , whit©, e i l i s e o u e s a n d sto n e c o n c r e tio n a r y b o d ie s o f i r r e g u l a r shape* b a s a l & f e e t c o n ta in abu ndant m olds of f o s s i l s c la y - c h o c o la te brown* sandy and g l a u c o n i t i c * h e te ro g e n e o u s 9 many molds of f o s s i l s g re e n sa n d - l i g h t g r e e n i s h gray to brown* a r g i l l a c e o u s * a bu ndan t molds o f f o s s i l s * n e a r to p a r e many i r r e g u l a r , c o r * c e n t r i ^ s t r u c ­ t u r e d l i m u n i i i c c la y s t o n e o r i r o n s t o n e c o n c r e tio n s * came o f which c o n ta in a c o re of l i g h t brow nish gray s i d e r i t e * 4 f e e t below to p i e an o y s t e r bed which c o n ta in s an abundance of i g t r e a g e l l a e f o r a i e and many o t h e r forme Base o f exposed s e c t i o n h issin g e e e tie a s e c t i o n c o n tin u e d s t a r t i n g a t to p o f out im m ediately so u th o f t o t t e r c h i t t o Greek b r id g e g l a u c o n i t i c sand - l i g h t g r e e n i s h gray t o brown* a r g i l l a c e o u s * few mcide of f o s u i t e * r e a l l y a deeply w eathered sandy m a rl o r c a l c a r e o u s sand c la y * medium gray* b lec k y and i i g n i t i c * g ra d in g down i n t o c la y * l i g h t g r e e n i s h gray* sandy and g l a u c o n i t i c * heterogeneous* s p a r i n g l y £ o s s i l i f e r o u e * s c a t t e r e d w eath ered s i d e r i t e c o n c re ­ tio n s near c e n te r g l a u c o n i t i c ©and - l i g h t g r e e n is h gray to yellow* very f i n e g rain e d * c a lc a r e o u s an d very f o s s i l i f e r o u e w ith i s t r e a e e l l a e forrolg and many o t h e r forms* abundant sm all c a lc a r e o u s ©oner©-

lio n s 3^*

o y s t e r bed * greenMU&d loaded w ith C e tr e a © yljtyeferftiq and many e t h e r forma? l i g h t g r e e n i s h gray t© y©liow-brown$ loos® to s l i g h t l y in d u r a te d ? most p ro m inent bed i n s e c t i o n

5*

g l a u c o n i t i c sand o r g re e n sa n d * l i g h t g r e e n i s h g ray t© yellow -brow n? banded a p p earan ce? brown bands a r e i n d u r a t e d and c o n ta in e a r t h y s l d e r i t e ? few t h i n s t r i n g e r s o f f o s e i l i f e ro u e greeneand? s i x i n c h , dark g r e e n , medium g r a i n e d , foe* s i l i f e r c u s g ree n sa n d s t r i n g e r one f o o t above base

36*

T o ta l t h i c k n e s s o f l o t t e r c h i t t o member C o n ta c t conform able

a RCHBSA

16^*

MARL k l B I K

sandy m arl - medium g r e e n i s h b lu e t o gray and y e llo w -g ra y ? a r g i l l a c e o u s , s p a r i n g l y g l a u c o n i t i c and h ig h ly f o s s i l i f e r one? le n s w ith a bun dant O c tre e g e ll a e f o r ia i a n e a r m iddle? two d i s ­ c o n tin u o u s 6 to 8 in c h ledges o f whit© to l i g h t g r a y , sandy l im e s to n e n e a r base? a b o u t 3 f e e t below to p i e a b e n t o n i t i c s e c t i o n i n which i r r e g u l a r i n c l u s i o n s o f b e n to n i t e and ben­ t o n i t i c c la y o c cu r i n a m a tr ix o f f e s s i l i f © r o u e m arl Base o f s e c t i o n a t ro ad l e v e l a t base of c u t - e l e v a t i o n 359* T o ta l

autubfcae s e c t i o n m easured - 66 £ *

T o ta l s e c t i o n m easured - 78^* n e a r l y com plete l o t t e r c h i t t o s e c t i o n s i m i l a r to t h e ty p e s e c t i o n i e exposed i n a cut on t h e county road on t h e so u th s id e o f £ o t t e r c h i t t o Creek 3 / 8 th e o f a m ile w est o f th e ty p e l o c a l i t y and i n t h e HZ of 3^ o f &3/T6K/RHB*

The s e c t i o n t h e r e i e le s s f o s a i i f f e r o u ©

a nd t h e t h i c k n e s s e s and sequence 01 oeds a r e s l i g h t l y d i f f e r e n t .

The

53

t o t a l t h i c k n e s s a s m easured by hand l e v e l i s 36 f e e t #

T his s e c t i o n

may he considered, an a l t e r n a t i v e ty p e s e c t i o n i n e a se th® o t h e r on® i e d e s tro y e d # -vs shown i n t h e d e s c r i b e d s e c tio n # t h e r e i e c o n s id e r a b le v a r i a t i o n i n t h e l i t he logy o f t h e i o t t e r c h i t t e * g re e n sa n d t o n o n - g l a u c o n i t i c eana a r e Pound*

A i l g r a d a t i o n s from

These sands v ary from

c a l c a r e o u s a n d m arly t o n o n - c a lc a r e o u s and from h ig h ly f o s s i l i f e r o u s to n e n -fo s s ilife re u s *

They c o n ta in p e l l e t s , p a r t i n g s # i n t e r b e d e and

l e n s e s of carb o n aceo u s c la y and shale*

Bom© o f t h e c la y i n c l u s i o n s

a r e t u b u l a r and f i l l e d w ith m a t r i x m a t e r i a l* a r e u s u a l l y i s t e r b e d d e d an d p o o rly bedded*

ifae d i f f e r e n t m a t e r i a l s o c c a s i o n a l l y th ey a r e

e v e n -re d d e d ana th in - b e d d e d and# i n r a r e i n s t a n c e s # th ey a r e c ro ss-b e d d ed *

one o f t h e i n d i v i d u a l beds can be t r a c e d any d i s t a n c e

a lo n g t h e s t r i k e *

The g l a u c o n i t e of t h e i o t t o r c h i t t o i s b o th l i g h t

and dark green i n c o l o r and i s much f i n e r g r a i n e d th a n t h e

in o n a

g la u c o n ite * B e n to n ite and b e n t o n i t i c c lay s i m i l a r i n a p p e a ra n c e and o c c u r ­ ren c e t o t h e b e n t o n i t e i n t h e ..rchuea, a r e found i n t h e i o t t e r c h i i i o a t a few l o c a l i t i e s *

:a r th y s i d e r i t e i s common In th® member*

hen

f r e s h * i t i e a l i g h t brow nish g ray c o lo r and c o n ta in s c o n s id e r a b le c lay* but i t w e a th e rs so r e a d i l y t h a t th® u n a l t e r e d m a t e r i a l i s r a r e l y se en on t h e o utcro p* .h e w eath ered l o t t e r c b i t t o o u tcro p i s always marked by weak c o n c r e t i o n a r y led g e s most of which a r e of brown# l im o n i ti e sa n d sto n e d e v elo p ed on t h e w eathered greeny.no. and g l a u c o n i t i c sana beds*

Ihey

re se m b le rh© c o n c r e tio n a r y b o d ie s in t h e vlnonu* but a r e n e v e r eo w e ll developed*

. ome of t h e le d g e s a r e of brown llra cm itic c la y ©ton® o r

54 i r o n s t o n e d e r i v e d from w e ath e re d e i d e r i t e * The c o n c r e tio n a r y b o d ies o f t e n c o n ta in m elds o f f o s s i l s and w eath ered g r a i n s o f g la u c o n ite * These c o n c r e t i o n s g r e a t l y a i u i n i d e n t i f y i n g t h e T O tte r c h itt© on t h e d e e p ly w e a th e re d o utcro p* Lower C o n tac t * The 1 © tie rc h itto -iirch u fira c o n ta c t i s conform** a b l e and g r a d a t i o n a l *

I n mapping t h i s member i t was found meat s a t i s ­

f a c t o r y t o a r b i t r a r i l y i n c l u d e &e much a s p o s s i b l e o f t h e x - o t i e r c h i i t o - t y p e m a t e r i a l i n t h a t member even i f t h i s p ro c e d u re in v o lv e d p l a c i n g le n s e s o f A rchusa-typ© m arl i n t h e 1o t t e r c h i f t o *

The p o s i t i o n of th e

c o n t a c t a t t h e i o t t e r c h i t t o t y p e l o c a l i t y was e s t a b l i s h e d on t h a t b a e ie *

The t h i c k n e s s r e l a t i o n s h i p s chow t h a t th e ty p e i o t t e r c h i t t o

s e c t i o n i s a t l e a s t i n p a r t contemporaneous w ith t h e upper .r e b u s a i n J a s p e r and C la rk e C o u n tie s ( s e e P l a t e 2)* T h is c o n ta c t r e p r e s e n t s a change o f c o n d i t i o n s s i m i l a r to t h a t r e p r e s e n t e d by t h e

ia e n & -b a s ic c o n t a c t i n e a s t e r n M i s s i s s i p p i *

T h ic k n e s s - The t h i c k n e s s o f t h e x o t t e r c h i t t o member rang®a betw een i£ ana 30 f e e t i n C l a r k e , J a s p e r and s o u t h e a s t e r n kewton C ounties*

I t r e a c h e s a maximum o f 36 f e e t a t t h e type l o c a l i t y and

becomes l e n t i c u l a r and l o s e s i t e i d e n t i t y i n n o r th w e s te r n Newton County* F o e e i i s * The in d e x f o s s i l Getreft e e lla e f o re a ia ra n g e s th r o u g h ­ out th e

o t t e r c h i t t o member*

In a d d it i o n * th e l e t t e r c h i t t © c o n ta in s

a l a r g e fa u n a which i s c l o s e l y r e l a t e d to t h a t o f t h e iirehusa* b u t l o c a l i t i e s where f r e s h f o s s i l s can be c o l l e c t e d a r e ra re *

The ty p e

l o c a l i t y i s t h e b e s t f o s s i l l o c a l i t y f o r t h i s member a s w e ll as one of th e beat

a u tu b b e e l o c a l i t i e s i n th e s ta te *

&>**#» smfe SMla saa£s£ I n t r o d u c t i o n * The name Gordon Creek i s ta k e n from a sm all c re e k which flow s th ro u g h .au tub bee s t a t i o n and which i e c ro s s e d by t h e ia u r e i-M e rid i& n highway (U* S# 1 1 } a s h o r t d i s t a n c e so u th o f t h a t sta tio n *

The ty p e s e c t i o n i s d e s i g n a t e d m® t h a t shown on th e p r o f i l e

a lo n g t h e highway ( s e e P r o f i l e B}*

A l l of t h e im p o rta n t f e a t u r e s o f

t h e l i t h e logy o f th e member a r e w e l l exposed a lo n g t h i s highway# ^itteo logy - The Gordon Creek member has th© same l i t ho logy a n d s t r a t i g r a p h i c r e l a t i o n s h i p s a s th e

i i p h a shale#

I t i s predom i­

n a n t ly a c arb o n ac e o u s s h a l e which v a r i e s i n c o l o r from b la c k to c h o c o la te brown to g r a y to r e d , depending upon th e s t a g e o f w eath­ e rin g #

G la u c o n ite and q u a r t s sand a r e abundant and i r r e g u l a r l y d i s ­

t r i b u t e d i n th e b a s a l few f e e t and sm all p o c k e ts and le n s e s o f t h a t m a t e r i a l a r e o c c a s i o n a l l y found w e ll up i n th© s e c tio n #

The lower

p o r t i o n i s c h a r a c t e r i s t i c a l l y a n e a r ly p u r e , biocky c l a y , w h ile th e u p p e r p a r t i s more s i l t y and ahaly#

: l&nt fra g m e n ts a r e found th ro u g h ­

o u t t h e s e c t i o n , b u t a r e more abun dant i n t h e u p p e r, e h aly p o r tio n # T h in , i r r e g u l a r p a r t i n g s and i n t e r b e d s of g r a y , l i g n i t i c , m icaceous s i l t a r e ab u n d an t i n th e upper p a r t o f t h e s e c tio n #

This t y p i c a l

l i t h o logy i s b e s t expoeea on t h e t y p e p r o f i l e in a cut along th e o ld nigbway im m ed iately e a s t o f th e p r e s e n t highway l o c a t i o n a t a p o i n t l«o m ile s n o r t h o f t h e highway o v e rp a s s n e a r

a u tu b b e e s t a t i o n and

a g a i n a t t h e ty p e l o c a l i t y of t h e , o t t e r c h i t t o member# The second f a c i e s o f t h e Gordon Creek exposed a lo n g t h e ty p e p r o f i l e i s t h a t o f a dark g r e e n i s h gray ( f r e s h ) to l i g h t g ray (w eath­ e r e d ) , l i g n i t i c , a r g i l l a c e o u s , s p a r i n g ly g l a u c o n i t i c s i l t or s i l t y sh a le # near

i b i s f a c i e s i s w e ll exposed in th e cut b e n eath th© o v e rp a ss /autubbee S t a t i o n and i n c u ts a lo n g t h e highway f o r s e v e r a l

56

m i l e s s o u th si* t h a t p o in t*

I t i s a c o m p a ra tiv e ly r a r e f a c i e s of t h e

member* t h i n beds o f l i g h t gray to w h i t e » p i a t y , s p a r i n g ly g l a u c o n i t i c , s i l i c e o u s s i l i s t e n s w ith a s u p e r f i c i a l resem b lan c e t o some o f t h e B a sic s i i t s t o n e s a r e common 1® t h e Gordon Creek i n Newton, J a s p e r and n o r th * w e s te rn C la r k s C ounties*

The b e s t developm ent o f th e s e bods i s found

i n t h e a r e a w est o f D e c a tu r, Newton County, where a f i v e f o o t s e c t i o n o c c u r s a t th e top of t h e member*

Dlsewhsre th e y occur a s two o r t h r e e

t h i n beds n e a r th e b ase o f t h e s e c tio n * s i x in c h s t r i n g e r o f

b e n t o n i t e i s found a t th e b a se o f

t h e Gordon Greek i n J a s p e r County and sm a ll q u a n t i t i e s o f l i g h t g ree n b e n t o n i t e o r b e n t o n i t i c c l a y a r e found a t t h e same h o rizo n a t s e v e r a l l o c a l i t i e s i n C lark e County* ower C o n tac t * The Gordon C r e e k ^ f e t i e r e h i t t o c o n ta c t i s con­ fo rm ab le and s h a r p l y d e fin e d *

I t i e v ery s i m i l a r i n d e t a i l s to th e

Zi lp h a - z in o n a c o n ta c t and r e p r e s e n t s th e same sequence o f ev en ts* The m a t e r i a l a t t h e c o n t a c t p r o p e r i s a h e te ro g e n e o u s m ix tu re o f c a r ­ bonaceous c l a y , g l a u c o n i t e and q u a r t s sand*

Downward from t h i s h o r i z o n ,

th e carbon aceou s c la y becomes i n c r e a s i n g l y r a r e , w h ile upward th e q u a r t z sand and g l a u c o n i t e become r a r e and d isa p p e a r* T h is c o n ta c t i s a good one on which to do d e t a i l e d f i e l d work* I t n o rm a lly comes a f o o t o r two above th e uppermost c o n c r e tio n a r y m a t e r i a l o f th e

o t t e r c h i t t o and can r e a d i l y he p ick e d on t h e outcrop*

T h ic k n ess - I n c o n t r a s t to t h e wide v a r i a t i o n s in t h i c k n e s s o f th e Z iIp h a , th e

ordon Creek member m a in ta in s © c o n s i s t e n t t h i c k n e s s

o f between 15 and 25 f e e t th ro u g h o u t i t s e x ta n t*

§7 * i l l g g a g e n f e f o r m i s ra n g e s up i n t o t h e b a s a l few f e e t ©f th e Gordon Creek*

Molde ©f f o s s i l s o c cu r o c c a s i o n a l l y i n

t h e b a s a l , g l a u c o n i t i c p o r t i o n o f t h e member, b u t no l o c a l i t i e s were fo und where f r e s h m a t e r i a l could be c o llo o te d #

Wo check has been

made on t h e s e s h a l e s f o r m i c r o f o s s i l s . L n d i f f e r e n t i a t a d Wautubbee g>f C entral. M i.s^lesfppi I n t r o d u c t i o n - The t h r e e - f o l d s u b d i v i s i o n of t h e

a u tu b b e e

f o r m a tio n o f e a s t e r n n i s s i s e i p p i can be s a t i s f a c t o r i l y c a r r i e d n o r t h ­ w est to Township 7 W orth, Kang© 11 T a e t, c e n t r a l wanton C©u*vty#

Beyond

t h a t tow nship t h e d i f f e r e n t f a c i e s become e© l e n t i c u l a r t h a t s a t i s ­ f a c t o r y s u b d i v i s i o n o f t h e s e c t i o n i© i m p r a c t i c a l and t h e fo rm a tio n i s u n d iife re n tia te d #

Ti.is u n d i f f e r e n t i a t e d m arine sequence c o n tin u e s

unbroken a lo n g t h e s t r i k e to t h e Yoekahockany K iver i n n o r th w e s te r n ^eake County#

i o r i b w e s t o f t h a t r i v e r t h e m arine m a t e r i a l s o c c u r

o nly a s d i s c o n ti n u o u s le n s e s which l i e n e a r t h e same s t r a t i g r a p h i c h o riz o n and which can b® t r a c e d i n t o t h e a r e a around t h e v i l l a g e o f T ew port, so u fn w e s te re

. t t a l a Tounty w ith o u t s e r i o u s d i f f i c u l t y #

I o r th w e e t o f dew eort th e a t r a t i g r a p h i © e q u i v a l e n t o f th e m arin e 'autubbee i s a h ig h ly l e n t i c u l a r s e c t i o n o f non-m arine sand s and c arbonaceous aha log* -litholoigy - Th® Yautubbee o f c e n t r a l M i s s i s s i p p i i e composed o f carbo naceo us s h a l e s , f e e e i l i f e r o u s to n o n - f o s s i l i f e r o u s g reo nsan ds and g l a u c o n i t i c s a n d s , n o n - g l a u c o n i t i c sands and f o s e i l i f e r o u s , sandy m arls#

The e s o t i o n i s e s s e n t i a l l y a h ig h ly i n t e r l e n e e d mass o f th e

t h r e e e a s t e r n M i s s i s s i p p i f a d e s o f th© form ation#

The lower p a r t

i s u s u a l l y composed of g r e e n s a n d e , g l a u c o n i t i c sands ana m a r l s , w hile

58 t h e Upper p o r t i o n i s t y p i c a l l y composed o f carbonaceous s h a l e s , b u t i n l o c a l a r e a s t h e s h a l e s ex te n d t o t h e base o f t h e s e c t i o n and i n o t h e r p l a c e s the sand© a r e found a t t h e top*

J a c e n t r a l Leake County

t h e r e a r e two 5 to 15 f o o t l e n s e s o f ehaly g l a u c o n i t i c ©and which l i e w e l l above th e s a i n body o f t h e vautubbee and a r e s e p a r a t e d fro® i t by non-marin© sands*

Thee© lease© a p p e a r to be d e p o s i t s which were

l a i d down d u rin g l o c a l , m inor advance© o f t h e sea and th e y a r e i n c l u ­ ded i n th© L&utubfeee i n o r d e r to keep a l l m arine m a te ria l© in t h a t fo rm a tio n * ^ower C o n ta c t • The lower c o n ta c t o f t h e "/autubbee o f c e n t r a l M i s s i s s i p p i i s a i 2 conform able a s f a r n o r th w e s t a s t h e Yoekahockany Liver*

Beyond t h a t p o i n t t h e main advance o f t h e

broken i n t o s e v e r a l l o c a l i s e d m inor advances*

au tu b b ee se a was

lh© d e ta il© of th e

c o n ta c t i n t h e a r e a s o u t h e a s t of t h e r i v e r a r e very s i m i l a r to th© a e t a i l s gi t h e

.rch usa-K o eciueko c o n ta c t in e a s t e r n &i©ei©eippi and

th© c o n t a c t form s a v a lu a b le mapping h o rizo n which i s o f te n marked by weak c o n c r e tio n a r y ledges* Thicknegs » The t h i c k n e s s o f t h e west e ra Lewton ana n o r t h e a s t e r n feet*

a u tu b b e e s e c t i o n i n n o r t h ­

e o t t C o u n ties ra n g e s from 45 to 75

no rth w estw ard a lo n g s t r i k e th e t h i c k n e s s v a r i e s somewhat b u t

g r a d u a l ly d im in is h e s to 12 f e e t a t t h e Yoekahockany

iv e r *

Th© i n -

d u e l o n of th e two m arin e l e n s e s ly in g above th e main boay of th© f o r m a tio n i n c r e a s e s the t h i c k n e s s to a maximum o f 75 f e e t in c e n t r a l Leake County*

l e v a t i c n e of t h e le n s e s o f m arine m a t e r i a l in th e

s e c t i o n n o rth w e s t or th e Yoekahockany R iv er show t h a t th e y l i e a t s l i g h t l y d i f f e r e n t h o r ia o n e , t h e maximum v e r t i s a l d i f f e r e n c e between t h e s e h o r iz o n s being a bo ut 40 f e e t *

The !*autubbe© bed© ©f c e n t r a l k i ie e i a s i p p i a r e l o c a l l y h ig h ly f® © silif© reu s* b u t t h e r e a r e few l o c a l i t i e s i n th e a r e a where s a t i s f a c t o r y c o l l e c t i n g i s p o s s i b l e .

;,© i n t h e case of

t h e r e t t e r c h i t t o * most of t h e f o e o i l i f e r o u e beds a re porous sand© which a r e d e ep ly lea ch e d and th® fo s s il© a r e seen a© m olds.

These

m elds a r e found in th e bed© a s f a r n o rth w e st a s th e m arine le n s e s a r e fo u n d .

ifa© b e s t f o s s i l l o c a l i t i e s i n th e c e n t r a l . . t e s i e e i p p i

a r e a a r e found i n t h e m a rls a t t h e b a se of t h e fo rm a tio n i n north** e a s t e r n w c c it and n o r t h w e s t e r n Newton C o u n tie s .

he bed© a t th e s e

l o c a l i t i e s c o n t a i n a b o u t t h e same fa u n a a s t h e a r c h u s a . C e tr e a g e ll a e f o r ia i a i s founo. a s f a r n o r th w e s t a s f o s s i l s a r e found i n th e fo r m a tio n . 2M £E*£ g * » * ate-Va Mamliar

I n t r o d u c t i o n - B eneath t h e q u a te rn ary sands and g r a v e l s i n n o r th w e s te r n no lms s and so u th w e ste rn C a r r o l l C ounties* t h e r e o u tc r o p s a t h i c k s e c t i o n o f carbonaceous s h a l e s which c o n s titu te © a d i s t i n c t i v e l i t h o lo g ic u n i t .

T here i e very l i t t l e s i m i l a r m a t e r i a l in th e 4h0

f e e t o f o v e r l y i n g u ea-m arin e C o c k f ie ld beds and th e © action below i s p red o m in an tly a non-m arine sand s e c t i o n w ith l e n s e s ox c arbonaceous s h a l e ana l i - n i t i c , s i l t y s h a l e . c n a le i s h e r e in named th e

from

xhia t h i c k s e c t i o n of carbonaceous

h i p p 's Greek s h a le* th e name being taken

n i p p ’ s Greek* a t r i b u t a r y to H a c k Creek in e a s t - c e n t r a l Holmes

County* M is s i s s i p p i * i’be Shipp*© Creek ©bale i s a t l e a s t in p a r t th e t t r a t i g r a p h i c e q u i v a l e n t o f th e m arine Jautub bee of c e n t r a l

i s s l e s i p p i b ecau se i t

lie© a t th e same s t r a t i g r a p h i c horizon i n an a r e a

a which so n -m a rin e

60

s e d i m e n ta t io n m s c o n tin u o u s th ro u g h o u t tapper ana m id d le cl&iborn© tim e*

The Shipp*® Greek o c c u p ie s a p o s i t i o n i n th e m iddle o f th©

s e c t i o n between th e to p o f th e The m arine

a u tu b b e e o c c u p ie s t h e earn© p o s i t i o n i n t h e © ectien on th e

o u tc ro p in c e n t r a I County*

I n o n a and th© to p o f th© C laiborn e#

i s e i s e i p p i and i n th e s u b s u r f a c e s e c t i o n i n Y&teo

The S h ip p ’ s Creek o u tcro p a l s o lie® a lo n g th e p r o j e c t i o n o f

t h e norm al s t r i k e o f the m arine

autubbee#

a ith ® lo ^ y - L ith o lo g y t y p i c a l o f thi® member i s e e l ! exposed a lo n g p r a c t i c a l l y every stream i n th© ^ o e ss H i l l s r e g io n o f n o r t h ­ w e s te rn Holme* and so u th w e ste rn C a r r o l l Counties#

rhe b e e t exposure®

a r e lound on a s e r i e s c , b l u f f s on Chicopa Greek and i t s t r i b u t a r y J o r d a n ’ s Branch i r h i l i i p * ® Creek, i n extreme n o r th w e s te rn ^okae® County where 60 to 100 f e e t ci th e s e c t i o n can be seen i n t h e f r e e d sta te *

Ih eee outcrop® a r e r e l a t i v e l y i n a c c e s s i b l e and so an exposure

i n a cut a lo n g th e county ro ad im m ed iately s o u th of th e i r o n b r id g e a c r o s s S h i p p 's Creek i n t h e G3 o f Ni5 o f s e c t i o n 28/t15H/k3K and a b o u t 4 m i l e s ( a i r l i n e , e a s t - n o r t h e a s t o f L e x in g to n , relate* County, ....isei e e i . p i was s e l e c t e d a® t h e type#

The s e c t i o n here i s *

COCKTICLD HGiilL.TIUtf 23*

sana - i r o n - s t a i n e d j i r r e g u l a r l y sodded to m aeeivej abundant s l a b - l i k e p i e c e s c f dark brown, l i m o n i t i c sa n d sto n e up to 2 in c h e s tfaiekj brown s i l t m an tle

'itbTliBBiiS - GKilnTICK CilXKi *G 14*

K Otitil* . luizM&iuki *• 1Vfo jLCTTCK

carbonaceous s h a le - c h o c o la te brown to l i g h t gray§ lam inated and w ith i r r e g u l a r p a r t i n g s ^nd i n t e r b e d e up to 4 in c h e s

61

t h i c k u i l i g h i g ra y soars® s i l t ; f r e s h m a t e r i a l h ig h ly l i g n i i i e and w ith a s o c c a s i o n a l f o s s i l l e a f ; f l a k y yeli©w~brown s l i t * s to n e co n cretio n ® a lo n g s i l t y p a r t i n g s ; a t th® top i s a t h i s limo: i v i o s a n d s to n e ledge o f t h e ty p e e©3ansoniy formed. os th e to p o f s h a l e s e c t i o n s by c i r c u l a t i n g g ro u n d -w a te r sand - g ra y t o y e llo w t o brown; very fin© g r a i n e d and looses few p a r t i n g s o f g ray s h a l e $ g ra d in g down i n t o 7^*

sand - s i m i l a r t o above but more p a rtin g ® and s t r i n g e r s o f g ray to c h o c o la te s h a l e w i t h abundant f l a k y e i I t s t o n e c o n c r e t i o n s i n t h e more w e a th e re d m a t e r i a l

£*

c arbo naceous s h a l e - c h o c o la te brown

6'

covered _ e c tio n c o n tin u e d b e n e a th b r i d g e

16*

carbon aceou s s h a l e - b lac k to c h o c o la te brown; la m in a te d ;

whole

mass r e g u l a r l y bedded, but i n d i v i d u a l lam inae e x tre m e ly i r ­ r e g u l a r and l e n t i c u l a r ; p a r t i n g s , i n t e r b e d s and p o c k e ts o f c o a r s e s i l t ; ab und an t frag m e n ts o f p l a n t s and an o c c a s i o n a l fo s s il lea f a t e r l e v e l o f b h ip p 'e Creek - e l e v a t i o n 334’ ( a l t i m e t e r ) 48*

T o ta l bhipp*s Creek s e c t i o n - b ase n o t exposed

t o t a l s e c t i o n m easured - 71 f e e t The Shipp*e Creek member i e much oore l e n t i c u l a r th an could p o s s i b l y be i l l u s t r a t e d on i l a t e #*

ih® carbonaceous ©hale® a r e i n t e r *

beddea and i n t e r l e r s e d w i t h s i l t s and sands in an e x tre m e ly comp lex manner*

he b e s t i l l u s t r a t i o n o f i b i s c o n d itio n i s found in « com­

p a r i s o n o f th e t y p e s e c t i o n w ith th® s e c t i o n exposed a t a b l u f f on

68 t h e s o u th s i d e o t ilhipp*e Crook on t h e Chuck owlniaey p l a c e a b o u t h a l f a m il e above th e ty p e l o c a l i t y and n e a r t h e c e n t e r o f s e c t i o n 87/T1SM/ R3S*

The e e e t i c n t h e r e is*

SBIFF* i, CRSBK SHAL^ M^tESR O f 80*

H3MATX0K

sand - l i g h t g r a y , w h ite and yelldw~brownj very f i n e g r a i n e d and m icaceo us; p a r t i n g s , s t r i n g e r s and i n t e r b e d s o f carbonaceous s h a l e ; t h i s bed changes l a t e r a l l y i n t o a carbonaceous s h a l e s e c t i o n a t th e low er end o f t h e b l u f f ( w i t h in a hundred y a rd s )

6 to 8 *

carbonaceous s h a l e * b lack to c h o c o la te brown; i r r e g u l a r p a r t i n g s o f medium g r a y , l i & n i t i c , m icaceo us c o a r s e s i I t and a few t h i n s t r i n g e r s o f b la c k l i g n i t e ; s h a l e n e a r l y p u r e c la y and c o n t a i n s an abundance o f p l a n t frag m e n ts

3 te 5'

sand - w h ite to yellow -brow n; bands and p a r t i n g s o f b l a c k , l i g n i t l c c o n c e n t r a t e s and brown, l i g n i f i e c l a y ; m ic ac eo u s; i n d i v i d u a l beds l e n t i c u l a r and c ro s s-b e d d e d

l£*

s h a l e o r c la y - d ark gray t o b la c k ; s i l t y and l i g n i t l c ; y e llo w is h e f f l c u r e s c e e c e on s l i g h t l y o x i d is e d s u r f a c e ; le n s e s o f l i g h t gray e d i t ; e x tre m e ly i r r e g u l a r s t r u c t u r e ; t h i s bed t r u n c a t e s u n d e rly in g bed

2 £*

c o a r s e s i l t - medium g ra y to brown; m icaceo u s; y e llo w is h ©ff l o u r e s c e n c e on s l i g h t l y o x id is e d s u r f a c e ; few i r r e g u l a r p a r t i n g s and o r i e n t e d b le b s o f g r a y , l i g n i t l c c la y

5*

s i l t y s h a l e or i n t e r l a m i n a t e d s i l t anu c la y - medium g ray to brown; l i g n i t l c and m icaceous; s t r u c t u r e o f whole ev en -b ed aed and o f i n d i v i d u a l lam inae h ig h ly i r r e g u l a r and l e n t i c u l a r :& ter l e v e l o f

>bipp'e Creek - e l e v a t i o n 840* ( a l t i m e t e r )

l o t a l s e c t i o n measured * 40 f e e t

63 i n a d d i t i o n to t h e carbonaceous s h a l e s add store o r l e s e l i g n i t i e s l i t s and sands* t h e Shipp*s Creek member c o n t a i n s a lew t h i n i n t e r b e d e o f b l a e k , im pure l i g n i t e * C o n ta c ts - The lower c o n ta c t o f th e S h ip p ’ s Creek i s conform­ a b l e and h ig h ly t r a n s i t i o n a l *

i t i s a r b i t r a r i l y drawn a t t h e b a se o f

t h e s e c t i o n i n which carbonaceous s h a l e s a r e t h e pred om in an t f a c i e s i n s o u th w e s te rn C a r r o l l and n o r th w e s te rn Holmes Counties*

as

shown

on P l a t e 2» t h e s e c t i o n i n t h e e a s t e r n H o lm es-so u th w estern A t t a l a County a r e a i s a l e n t i c u l a r mass o f carbo naceo us s h a l e s and r u n - g l a u ­ c o n i t i c sa n d s which cann ot be s a t i s f a c t o r i l y s u b d iv id e d and th e b a s a l c o n t a c t i s a r b i t r a r i l y p r o j e c t e d th ro u g h t h i s a r e a on c o n v e n ie n t c a r ­ bonaceous s h a l e l e n s e s i n o r d e r to J o i n t h e b a s a l c o n ta c t o f th e m arine -autubbee# The u p p e r c o n ta e t i e a l s o conformable#

i t v a r i e s from s h a r p l y

d e f i n e d t o t r a n s i t i o n a l * b u t i s a much more d e f i n i t e h o r is e n th a n th e low er c o n t a c t » s i n c e t h e r e i s l i t t l e carb o n aceo u s s h a l e i n t h e Gockf i e l d s e c t i o n i n Holmes and rasoo C ounties#

T his c o n ta c t i s p r o j e c t e d

a c r o s s so u th w e ste rn A t t a l a County on carbonaceous s h a l e le n s e s to j o i n t h e u pper m arine

a u tu b b e e c o n ta c t*

Both t h e u p p e r and low er c o n t a c t s

a r e dashed on t l a t e 1 th ro u g h o u t t h e a r e a n o rth w e s t o f th e rockahockany R iv e r b ecause o f t h e i r a r b i t r a r y n a t u r e i n t h a t are a* T h ic k n e s s - The maximum development o f t h e S hipp’ s Creek i s re a c h e d a lo n g th e b l u f f e which b o rd e r th e a l l u v i a l v a l l e y o f t h e L i e s i s s i p p i River*

The t h i c k n e s s o f th e member hero i s a b o u t SSOQ f e e t*

t h a t f i g u r e b e in g d e riv e d by r e f e r e n c e to s u b s u rfa c e c o n to u rs on top th e

in o n a.

The t h i c k n e s s d e c r e a s e s r a p i d l y eaetw ard and i e o nly ab o u t

65 f e e t i n t h e G hipp's Greek are a*

The a r b i t r a r i l y d e fin e d s e c t i o n

i n e lu d e d i n t h e o h ip p #e Creek a c r o s s e a s t e r n Holiness and so u th w e ste rn

64 A t t a l a C o u n tie s a v e r a g e s a b o u t 40 f e e t i n t h ic k n e s s * F o s s i l s - F o s s i l le a v e s o c c u r th ro u g h o u t t h e Shipp*© Creek b u t a r e nowhere abundant#

They have n o t been s t u d i e d i n d e t a i l #

Sm al tatem



££* aalgltea ftgasttta

D i s t r i b u t i o n * The d i s t r i b u t i o n o f t h e Wautubbee o u tc ro p i s sheen on F l a t * 1*

i t i s an i r r e g u l a r b e l t a v e r a g in g a b out two m il e s

i n w id th and ra n g in g from o n e - h a l f t o s i x m ile s wide which e x te n d s from t h e A la b a m a -M is siss ip p i s t a t e l i n e n e a r C r a n d a l l, C la rk e County n o r th w e s t a c r o s s t h e s t a t e to th e b l u f f s i n n o rth w e s te r n Holmes and s o u th w e s te r n C a r r o l l C ounties# T opographic E x p re s s io n «# The weak c arb onaceo us s h a l e s which c o n s t i t u t e t h e Gordon Creek member i n e a s t e r n M i s s i s s i p p i and t h e u p p e r p o r t i o n o f t h e u n d i f f e r e n t i a t e d Wautubbee o f c e n t r a l

;is siss ip p i

g iv e r i e e t o a d i s t i n c t i v e to p o g r a p h ic f l a t o r bench which g r e a t l y a i d s i n mapping t h e form ation#

The e t h e r beds o f t h e s e c t i o n have

no d i s t i n c t i v e to p o g r a p h ic i n f lu e n c e and t h e i r o u tc ro p i s a c o n t i n ­ u a t i o n o f t h e sand h i l l s to p ograp hy o f t h e C o c k fie ld and Kosciusko fo rm a tio n s # o i I s * The m a t e r i a l s o f t h e Wautubbee g iv e r i s e to a number o f d i f f e r e n t so ils#

The s p a r i n g l y g l a u c o n i t i c t o n o n - g i a u c o n i i i c

sa n d s g iv e r i e e t o f i n e sandy loams o r f i n e sa n d s o f th e H uston» G r e e n v i l l e , Orangeburg and N o rfo lk s e r i e s which have been d e s c r ib e d un d e r t h e s o i l s o f t h e Neshoba sand on page 22#

The groeneando and

h i g h ly g l a u c o n i t i c sands g ive r i s e to f i n e sandy loams o f th e Nacog­ d oches and a l l i e d s e r i e s d e s c r ib e d u nder s o i l s o f th e Winona and th e c a rb o n a c e o u s s h a l e s g iv e r i s e to t h e d i s t i n c t i v e Boswell and Susque­

65 hanna v a ry f i n e sandy o r s i l t y loams d e s c r i b e d u n d e r s o i l s o f th e Z i Ip ha* D e p o s itio n a ! C o n d itio n s * The d e p o s i t i o n of t h e w&utubbee m e i n i t i a t e d by an advance o f t b e se a o v e r th e Kosciusko d e l t a i c p la in * The maximum n o r t h e r n e x t e n t o f t h i s advance was to t h e l a t i t u d e o f s o u th w e s te rn

t t a l a County*

The d e c r e a s i n g t h i c k n e s s and l i t h o l o g i e

changes o f t h e fo r m a tio n a lo n g s t r i k e i n d i c a t e t h a t t h i s advance prefer­ a b ly d i d n e t o c cu r s i m u lta n e o u s ly th r o u g h o u t th e a r e a , but was i n i t i a t e d i n e a s t e r n M i s s i s s i p p i and g r a d u a l l y extend ed n o rth w ard t o i t s maximum advance*

i f s o , th e u p p e r p a r t o f t h e Kosciusko and th e lower p a r t o f

t h e C c e k f ie ld f o r m a tio n s o f w e stern M i s s i s s i p p i a r e t h e tim e equiva* l e s t s of p a rt o f th e

a u tu b b e e s e c t i o n i n e a e te r n M i s s i s s i p p i *

The d is a p p e a r a n c e o f th e m arin e Wautubbee s e c t i o n i n so u th ­ w e s te rn

.t t a l a County i s n e t due to o v e rla p o r t r u n c a t i o n o f th e

m a rin e s e c tio n * 1*

T h is i s e v id e n c e d by;

The m arin e l e n s e s i n s o u th w e ste rn A t t a l a County do n o t

l i e a t t h e same s t r a t i g r a p h i c h o r is e n a s th e y would i f th e y were rem nants o f a fo rm e rly c o n tin u o u s se c tio n * 2*

The carbonaceous s h a l e s and m arine sands o f t h e Wautubbee

e x h i b i t a normal and conform able r e l a t i o n s h i p i n th e a r e a where it: e m arine s e c t i o n d is a p p e a rs *

The carb o n ac e o u s s h a l e s which n orm ally

o v e r l i e th e m arine beds a r e p r e s e n t throughout*

They would be a b s e n t

had t r u n c a t i o n occu rred* 3*

The fh u tu b b ee beds become p r o g r e s s i v e l y more s h a llo w -w a te r

a e p e s i t s n o rth w estw ard a lo n g s t r i k e * T h is d is a p p e a r a n c e o f a m arin e s e c t i o n i s an example o f what p ro b a b ly

66 happ en s t© a i l m arin e s e c t i o n s i n t h e T e r t i a r y o f t h e $ u l f C o a s t a l i l a i n i s t h e a r e a o f maximum m arin e advance*

i n such an a r e a non-mar**

i n e s e d im e n ta tio n o c c u rs on t h e d e l t a i c p l a i n s im u lta n e o u s ly w ith m a rin e s e d im e n ta tio n j u s t o f f - s h e r e and m ino r r e t r e a t s and advancee ©f t h e s e a pro duce an i n t e r l e a v i n g o f t h e two f a c i e s # The ahundanee o f t h e l a r g e o y s t e r * Cstre et s e l l a e f o m i e * and o t h e r &h a Ilo w -w a te r forms* t h e c la y i n c l u s i o n s and t h e sandy n a t u r e o f t h e Archuea s a r i i n d i c a t e t h a t i t was d e p o s i te d f a i r l y n e a r sh o re i n c l e a r , sh a llo w w a te r s i n which lime was b e in g p r e c i p i t a t e d #

The

lac k of b ed d in g and l i t h o l o g i c b re a k s and th e homogeneity o f th e m a t e r i a l s i n d i c a t e uniform c o n d i t i o n s th ro u g h o u t i t s d e p o s itio n *

The

i r r e g u l a r bedding and l e n t i c u l a r n a t u r e o f th e beds o f th e I © t t e r c h l t t o i n d i c a t e t h a t i t was d e p o s i t e d n e a r e r sh o re th a n t h e Archuea i n an e n v iro n m en t i n which c u r r e n t a c t i o n was q u i t e stro n g *

This s h a llo w ­

i n g o f t h e eea co rre sp o n d e d c lo s e l y to c o n d i t i o n s d u rin g

in o n a time#

The g reen ean d e and g l a u c o n i t i c sa n d s of t h e u n d i f f e r e n t i a t e d

a utu bbee

o f c e n t r a l & i s e i s e i p p i were d e p o s ite d u n d e r t h e same c o n d it i o n s ae th e ie tte r c h itte * m arin e c o n d it i o n s were b ro u g h t t o a c l o s e by an advance o f t t e d e l t a i c p l a i n o v e r t h e sh a llo w m arine d e p o s i t s i n t h e same manner t h a t t h e d e p o s i t i o n o f t h e Z lip h a ended t h e T a lla h a tta -W in o n a m arine epoch# The d e p o s i t s which were l a i d down d u rin g t h i s change from m arine to no n-m arine c o n d itio n s were in co r;..cra te d in th e s e c t i o n a s th e Gordon Creek s h a le and th e carbonaceous s h a l e s o f th e u pp er c e n tr a l M ississip p i*

autubb ee o f

The sharp n a t u r e o f t h e Gordor Treek -1 o t t e r c h i t t o

c o n t a c t i n d i c a t e s t h a t t h i s change was v e ry r a p i d i n e a s t e r n ; i s s i s e i p p i * b u t t h e le n s a e o f green aand and g l a u c o n i t i c sand in t h e carbonaceous

$7 s h a l e s th ro u g h o u t c o n t r o l l i i s s i s a i p p i anti above th e main body o f t h e f o r m a tio n i n c e n t m l ^,oake County p o i n t to many minor* l o c a l i z e d ad** vaneoo o f t h e se a i n t h a t area* The t h i c k , non-m arine s e c t i o n between t h e to p o f t h e T iip h a a n d t h e to p ei' t h e O o e k fie ld i n w e ste rn M i s s i s s i p p i i n d i c a t e s unbroken d e l t a i c p l a i n d e p o e i t i o n a l c o n d it i o n s th ro u g h o u t K o sc iu sk o » autubbo© and O o e k fie ld tim e s i n t h a t area*

During S h i p p 's Creek tim e th e

s h o r e l i n e a p p a r e n t l y drew n e a r t h e n o r th w e s te r n Holm eo^southwestern C a r r o l l County a r e a and marshy c o n d it i o n s p ro b a b ly e x i s t e d w h ile t h a t member was d e p o s ite d *

68 COCKFISLD FOBtlATXQN I n t r o d u c t i o n ~ The beds i n M i s e i s s i p o i which a r e called . Cock* f i e l d i n t h i s r e p o r t were f i r s t n o te d by Hilg&rd ( I T ) i n i860* h u t lows

(1 8 ) f i r s t gave them a fo rm a l name, c a l l i n g them th e O o e k fie ld

l i g n i t e member o f th e Li ebon fo rm atio n * them b o th Cockfi&ld and Yegua*

L a te r author® have c a l l e d

L o st o f t h e s e w riter® have r e s t r i c t e d

t h e C c c k f le ld o r Yegua to t h e upper* mere s h a ly p o r t i o n o f t h e s e c t i o n h e r e i n c a l l e d O oekfield*

i n t h i s r e p o r t t h e fo rm a tio n i s expanded t o

i n e l u d e a l l beds below t h e Moody*® Branch ( b a s a l Jackson) and above th e

au tub bee*

T h is usage i s i n agreem ent w ith t h e usage o f th e term

C o c k fie ld i n U s u ie ia n a where th e ty p e l o c a l i t y i s s i t u a t e d and g iv e s t h e fo rm a tio n a d e f i n i t e b a s a l c o n ta c t r a t h e r th a n an a r b i t r a r y and h ig h ly t r a n s i t i o n a l one* s t e n s e l (19) has summarised th e h i s t o r y o f t h e names Yegtta and C ook field *

Be p o i n t s c u t t h a t th e ty p e l o c a l i t y o f t h e Yeg.ua. i s

i n r e a l i t y a p a r t o f t h e m arine C ro c k e tt fo rm a tio n and t h a t t h e term L u fk in has p r i o r i t y o v e r t h e t e r n legua*

The only p o i n t i n f a v o r o f

r e t e n t i o n o f t h e term Yegua i s i t s common usage*

Cn th e o t h e r hand

t h e type s e c t i o n o f th e C o c k f ie ld i s r e p r e s e n t a t i v e o f th e l i t h c l o g y o f t h e fo rm a tio n and o c c u rs n e a r th e m id d le of th© O o e k fie ld se c tio n * The term C o c k fie lo does n o t have p r i o r i t y e v e r e i t h e r Yegua o r i i i f k i n , (1 7 ) B* v?m H ilg a rd * R eport on th e Leo logy and A g r i c u l t u r e o f t h e S t a t e o f L i s e i s s i o p i ( J a c k s o n , tf.iee** B* B arksdale* I 8 6 0 )* pp* 127*128* (1 8 ) 3* R. Lowe* " M ie e is s ip p i* I t s Leo logy* Geography* L o iie and M in e ra l R e s o u r c e s ," & ie s » J e o l * purvey B u l l * A! (1915)* p. 77* ( 19) fU B* o t e n s e l * '’The Yegua rrab le m * " Texas Bureau of :: c a n o n ic apology 2241 U 9 3 9 ) , p p . 847-910.

69 b u t i e w e ll e s t a b l i s h e d in

l i t e r a t u r e and i s p r e f e r r e d o v e r

Yegua i n t h i e r e p o r t* The name O o e k fie ld was proposed by Vaughn (SO) i n 1895*

He

c a l l e d t h e s e c t i o n th e " C e c k s f ie id F e rry bode” a f t e r a l o c a l i t y i n G ra n t P a r i s h , L ouisiana*

Veateh ( S I ) l a t e r changed th e s p e l l i n g

s l i g h t l y and a b b r e v i a t e d t h e name to C ockfield* The C o c k f ie ld o f T i e s i e e i p p i has b e e r c o n s id e r e d b o th a mem** h e r o f t h e . i s b o n fo rm a tio n and a s e p a r a t e f o m a t i o n *

The te n d e n c y

i n l a t e r r e p o r t s has been t o g iv e i t f o r m a tio n a l rank and t h a t p r o ­ c e d u re i e fo llo w e d i n t h i s r e p o r t b ecause t h e s e c t i o n i e a w e l l - d e ­ f i n e d l i t h o l o g ic u n i t which has a wide a r e a l d i s t r i b u t i o n # L ith e logy «►The l i t h o l o g y o f t h e G o e k fie ld bede i s e s s e n t i a l l y t h e ease a s t h a t o f t h e io e c iu e k o s e c tio n *

The b a s a l 25 t o 125 f e e t

o f t h e fo rm a tio n a r e composed o f m assiv e t o h ig h ly c ro s s - b e d d e d , i r o n - s t a i n e d sands*

upward i n t h e s e c t i o n l e n s e s o f s h a le become

more and more abundant and u s u a l l y pred o m in ate o v e r th e sa n d s In th e upperm ost p a r t o f th e form ation*

The s h a l e s a r e of b o th th e carbon­

a c e o u s and l i g a i t i c , s i l t y ty p e s d e s c r i b e d under t h e l i t h o l o g y o f t h e Kosciusko*

The t r a n s i t i o n from th e b a s a l , sandy p o r t i o n to t h e

u p p e r sand and s h a l e p a r t o f t h e s e c t i o n i s so g ra d u a l t h a t no l o g i c a l s e p a r a t i o n e f th e e e two f a c i e s can be made in th e f i e l d # he shown on F l a t s 2 , a marked l i t h c l o g i c change o c c u rs i n th e -© c k fie lL s e c t i o n in w eetern L 'ie c le s i; pi*

On th e bluff© in w e ste rn

(2 0 ) T# V* Vaughn, "The s t r a t i g r a p h y o f N o rthw estern rAu:er« G e o l o g i s t * Vo I* 15 ( 1 8 9 5 ), p# 220*

o u ie ia n a ,"

(21) A. C# V eateb, "The Underground a t e r e o f N o rth ern L o u isia n a and S o u th e rn A rk a n s a s ,* L o u is ia n a Geo A* Mry

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a lo n g t h e Jackson f a u l t on L i t t l e L tave Creek a b o u t 3 m ile s n o r t h o f J a c k s o n , C larke County» Alabama* The e a s t e r n M i s s i s s i p p i s e c t i o n which i s e q u iv a le n t t o t h e above

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