New record of large Foraminifer from thae Early Eocene...

Fragm. M i n . Pal. 7. 1976.

New record of large Foraminifera from the Early Eocene rocks of Gabel el Shaghab, Esna, Upper Egyptom

Abbas Ib rah im K E N A W Y Assiut University, Geology Department, Assiut, Egyptom

A B S T R A C T : Some 18 species of L o w e r Y p r e s i a n l a rge f o r a m i n i f e r a a re desc r ibed here f r o m the E a r l y Eocene r o c k s of Gabal E l Shaghab, Esna, Upper E g y p t . Some of these l a r g e f o r a m i n i f e r a a re r eco rded f o r the f i r s t t i m e i n E g y p t . The r e s e m b l e those desc r ibed by DA V I E S & P I N F O L D (1937) f r o m the Punjab Salt Range, I n d i a . T h i s suppor t the Idea of the p r e v i o u s exis tance of an a r m of the Indian sea w h i c h extended to the Saha ra Reg ion of N o r t h A f r i c a .

I N T R O D U C T I O N

The L o w e r Eocene i n Upper Egypt , s t re tches on bo th sides of the N i l e V a l l e y f r o m the v i c i n i t y of Esna i n the south, whe re they o v e r l i e the Paleocene shales , and gent ly dip n o r t h w a r d s (1-2°) t i l l a p p r o x i m a t e l y the l a t i tude of A s s i u t , i n the n o r t h , where the M i d d l e Eocene r o c k s g r a d u a l l y o v e r l i e the L o w e r Eocene. These l a t t e r L o w e r Eocene a re a l so developed i n the Quse i r -Safaga r e g i o n of the Red Sea area and i n the Egma P la teau of the Sinai P e n i n s u l a . T o the wes t of the N i l e , the L o w e r Eocene rocks extend wes twa rds to the K h a r g a Oasis i n the W e s t e r n D e s e r t and extend f u r t h e r south to the wes t of A s w a n at K u r k u r .

The sys temat ic study of the L o w e r Eocene rocks i n Egypt s ta r ted by Z I T T E L (1883) who in t roduced the t e r m " L i b y s c h e Stufe" to inc lude the E a r l y Eocene r o c k s of Egypt , p a r t i c u l a r l y where they a re v e r y w e l l developed i n the w e s t e r n (Libyan) Dese r t , i n the scarp around the F a r a f r a O a s i s . Z I T T E L subdivided h i s L ibysche Stufe i n t o " U n t e r l i b y s c h e Stufe" c h a r a c t e r i z e d by the presence of s p h e r i c a l A l v e o l i n e s and "Ober l i bysche Stufe" w i t h elongate A l v e o l i n e s and hence the name " A l v e o l i n e n K a l k " used i n the Egypt ian E a r l y Eocene s t r a t i g r a p h y .

B A R R O M à H U M E (1902) c l a s s i f i ed the L o w e r Eocene r o c k s of Gabal S e r r a i and Gabal A b u Had sect ions at Qena in to the S e r r a i l imes tone w h i c h i s composed of N u m -m u l i t i c l i m e s t o n e , nodula r l i m e s t o n e , and banded f l i n t s e r i e s .

H U M E (1911) not iced that the E a r l y Eocene rocks at L u x o r ( H U M E ' s L u x o r type) a re c h a r a c t e r i z e d by the abundance of O p e r c u l i n a l i b y c a , L u c i n a thebaica, and other l a r g e echinoids , whereas at Qena (HUME* s Qena type) , i t i s non fos s i l i f e rous and i s c o m -

posed of wh i t e l imes tone w h i c h i s s i m i l a r to the u n d e r l y i n g c h a l k un i t , t h i s l a t t e r l imes tone i s some t imes co l l ed Sera i l i m e s t o n e . Hume suggested the f o l l o w i n g paléonto log ie zonat ion f o r the E a r l y Eocene r o c k s i n Egypt:

3 . Ca l l i anassa n i l o t l c a / S i s m o n d i a l ogo the t i Zone (=Upper L i b y a n ) . 2 . Os t r ea m u l t i c o s t a t a Zone )

) ( = L o w e r L i b y a n ) . 1 . O p e r c u l i n a l i b y c a Zone )

F O U R T A U (1912) subdivided the Egyp t i an L o w e r Eocene r o c k s i n to two zones as f o l l o w s :

1 . L i m e s t o n e w i t h A l v e o l i n e s (which he equated w i t h the Y p r e s i a n and C u i s i a n . 2 . L i m e s t o n e w i t h O p e r c u l i n a L i b y c a and abundant f l i n t nodules (which he c o r r e l a t ed w i t h both the Thane t ian and Sparnac ian) .

BOUSSAC (1913) studied the Eocene l i m e s t o n e capping Gabal E l Shaghab and r e c o r d e d N u m m u l i t e s a tac icus , O p e r c u l i n a sp . and Conoclypeus cono ides . He cons idered i t to the L u t e t i a n age.

B L A N C K E N H O R N (1921) ment ioned that the " L o w e r L i b y a n " alone was d e s c r i b e d to have a th ickness r ang ing between 90 m a t Gabal A l - G h a r r a h and 200-300 m i n the L i b y a n (Western) D e s e r t Oas is , be ing rep resen ted by whi te g r a n u l a r o r shaley, r a r e l y , o o l i t i c l imes tone ( somet imes developed as Ope rcu l ina , A l v e o l i n a , o r L i t h o t h a m -n i a l i m e s t o n e ) . I n add i t ion m a r l s and c l a y s . He mentoined tha t both the " L o w e r and Upper L i b y a n " were equated w i t h the N u m m u l i t e s p lanula tus beds i n w e s t e r n Europe , and hence cons idered to be coeva l w i t h the Lond in ian , Y p r e s i a n o r C u i s i a n s tages .

C U V T L L I E R (1930) used the t e r m E o n u m m u l i t i c to r ep lace Z I T T E L ' s " L i b y s c h e Stufe" and w h i c h was rough ly c o r r e l a t e d w i t h the type Y p r e s i a n . He concluded that the E a r l y Eocen r o c k s a re represen ted on ly by the upper beds of the E o n u m m u l i t i c , whereas the basa l E o n u m m u l i t i c i s m i s s i n g i n Egyp t .

HASSAN (1953) r eco rded N u m m u l i t e s d e s e r t i and N . g lobu lus f r o m a t h i n bed a t the base of the L o w e r L i b y a n i n Gabal E l - T e r and Gabal U r n E l - G h a n a y e m , K h a r g a Oas i s . T h i s bed i s u n d e r l a i n by the Esna Shal f o r m a t i o n , and i s o v e r l a i n by the L o w e r L i b y a n , w h i c h contains O p e r c u l i n a l i b y c a SCHWAGER, Ope rcu l ina c f . j i w a n i D A V I E S , Opercu l ina s p . ; N u m m u l i t e s g lobulus L E Y M E R I E , N . subramondi DE L A H A R P E , N . r a m o n d i D E F R A N C E ; O r b i t o i d e s nud imargo SCHWAGER; A s s i l i n a n u i DE L A H A R P E , A s s i l i n a dandot ica D A V I E S . He assigned an E a r l y Paleocene age (Mont ian o r Thanetian) to th i s bed w i t h N u m m u l i t e s d e s e r t i , and an Upper Paleocene age to the Upper beds .

SAID (1960) in t roduced the f o r m a t i o n a l name "Thebes F o r m a t i o n " typ i f i ed by the m o r e o r less 290 m . t h i c k l i m e s t o n e sequence w i t h abundant f l i n t bands of Gabal Gurnah, on the w e s t e r n bank of the N i l e fac ing L u x o r .

B I S H A Y (1961) subdivided the E a r l y Eocene rocks east of the N i l e between A s s i u t and M i n l a i n t o a l o w e r u n i t of non fos s i l i f e rous l imes tone w i t h f l i n t (the A s s i u t i F o r m a t i o n ) . He d i s t ingu ished two biozones i n the L o w e r Eocene of Wad i A s s i u t i ( M a n -fa lu t F o r m a t i o n ) : a l o w e r biozone c h a r a c t e r i z e d by the presence of D i s c o c y c l i n a n u d i m a r g o , D . a r c h i a c i , D . variáns, N u m m u l i t e s p o m e l i and N . s ta t i cus and an

upper b iozone c h a r a c t e r i z e d by the presence of N . a tac icus , N . d i s co rb inus and O r b i t o l i t e s p h a r a o n u m .

E L - N A G G A R (1970) suggested the t e r m " L i b y a n D e s e r t G r o u p " f o r the r o c k s o v e r l y i n g the Esna Shale un i t and subdivided i t as f o l l o w s : f r o m base to top:

( a . Gurnah Ca lca reous Shale M e m b e r . ( The L u x o r * F o r m a t i o n ( ( ( b . Thebes l imes tone M e m b e r .

L i b y a n D e s e r t ( G r o u p . (

( ( D r u n k a F o r m a t i o n .

Fig. 1

He gave the L u x o r F o r m a t i o n an E a r l y Eocene (Ypres ian) age, w h i l e the D r u n k a F o r m a t i o n an e a r l y Midd le Eocene (basal Lu t e t i an ) age.

K E N A W Y (1972) r e co rded 16 species of l a r g e f o r a m i n i f e r a f r o m the Triebes F o r m a t i o n at T a r a m s a sec t ion , wes t of Qena, and subdivided the success ion i n t o two zones:

1. Upper N u m m u l i t e s p lanu la tus Zone, r i c h w i t h N . p lanu la tus toge ther w i t h N . b u r d i g a l e n s i s , N . p a r t s c h i , N . aqu i tan icus , N . m u r c h i s o n i , N . p r a t t i , N_. aff . d i s t a m s ; D i s c o c y c l i n a stephensoni, D . m e s t i e r i and A k t i n o c y c l i n a sp . He a t t r i bu t ed th i s zone to the Upper Y p r e s i a n .

2. L o w e r , N u m m u l i t e s s o l i t a r i u s Zone w h i c h i s c h a r a c t e r i z e d by the presence of N u m m u l i t e s s o l i t a r i u s , N . g lobulus , N . a tac icus and Opercu l ina L i b y c a of L o w e r Y p r e s i a n age.

OMAR A , E L - T A H L A W I and K H A L I F A (1972) s tudied the a r e a of Gabal El-Shaghab, near Esna, and d iv ided the L o w e r Eocene r o c k s there i n t o three r o c k un i t s f r o m base to top as fo l l ows :

1. The H a m i d a t M e m b e r composed of l i m e s t o n e w i t h pe lecypod cas ts , p a r t i c u l a r l y L u c i n a thebaica .

2 . The Dabbabia M e m b e r composed of cha lky l i m e s t o n e w i t h N u m m u l i t e s sp . and O p e r c u l i n a sp .

3 . The Shaghab M e m b e r composed of h i g h l y f o s s i l i f e r o u s s i l i c i f i e d l i m e s t o n e .

M o r e o v e r , these authors d i v i d e d the success ion in to f ive b i o s t r a t i g r a p h i c zones based on m i c r o f o r a m i n i f e r a :

1 . G l o b o r a t a l i a subbotinae - Pseudohas t iger ina w i l c o x e n s i s Zone of l o w e r L o w e r Eocene age .

2. L u c i n a thebaica Zone of l o w e r L o w e r Eocene a l s o .

3 . N u m m u l i t e s a tac icus Zone of m i d d l e L o w e r Eocene .

4 . O p e r c u l i n a l i b y c a Zone of midd le L o w e r Eocene.

5. O s t r e a m u l t i c o s t a t a Zone of upper L o w e r Eocene.

The above r e v i e w of l i t e r a t u r e , c l e a r l y shows that the d i s t r i b u t i o n of l a r g e f o r a m i n i f e r a i n the L o w e r Eocene r o c k s of Egypt has not been thorough ly surveyed y e t . In o r d e r to f u l f i l l t h i s r e q u i r e m e n t the l a rge f o r a m i n i f e r a of the s i l i ceous and chalky l imes tones of Gabal E l Shaghab on the eas t e rn side of the N i l e V a l l y , about 25 k m n o r t h of Esna ( F i g . 1) a re s tud ied i i n some d e t a i l and the exact age of the success ion i s a cco rd ing ly deduced.

Fig. 2

LCompact marl. 3-Nummulitic limestone.

2-Mariy limestone. 4-Silicified limestone.

THE EARLY EOCENE ROCKS OF GEBEL EL SHAGHAB

T H E STUDIED SECTION ( F i g . 2)

Gabal E l Shaghab i s composed m a i n l y of L o w e r Eocene l imes tone and i n some areas the upper p a r t of the Esna Shale c r o p s out f r o m unde rnea th . I n the f o l l o w i n g the l imes tone succession i s d i s c r i b e d i n some d e t a i l .

Bed N o . L i t h o l o g y Th i cknes s (me te r )

4 G r e y i s h - w h i t e s i l i ceous l i m e s t o n e , h a r d , compac t w i t h Os t rea m u l t i c o s t a t a and N u m m u l i t e s sp . 60

3 Snow w h i t e , l i g h t g r ey m a s s i v e chalky l i m e s t o n e w i t h abundant N u m m u l i t e s , Ope rcu l i na , Rhan iko tha l i a and A s s i l i n a . 9 6

2 H a r d m a r l y l i m e s t o n e w i t h sca t te red f l i n t y bands w i t h abundant pelecypods, p a r t i c u l a r l y L u c i n a theba ica . 60

1 Whi te compac t m a r l . 20

T o t a l 236

The l a r g e f o r a m i n i f e r a i n the s tudied sec t ion :

Some 18 species of l a r g e r f o r a m i n i f e r a a re r e c o r d e d i n the l imes tone of the Thebes F o r m a t i o n of Gabal E l Shaghab sec t i on . Some of these l a r g e f o r a m i n i f e r a a re here descr ibed and i l l u s t r a t e d f o r the f i r s t t i m e i n E g y p t . The d i f f e r en t species w e r e separated f r o m the cha lky l i m e s t o n e and f r o m the upper s i l i c i f i e d l i m e s t o n e (Bed 2), a t the top of the s ec t i on . These are : N u m m u l i t e s a tac icus L E Y M E R I E , N . g lobulus L E Y M E R I E , N . s o l i t a r i u s D E L A H A R P E , Opercu l ina j i w a n i D A V I E S , O p e r c u l i n a j i w a n i DA V I E S grand i s n . subsp . , O p e r c u l i n a subsalsa D A V I E S , O p e r c u l i n a pa ta lens i s D A V I E S O p e r c u l i n a subammonea D O N C I E U X , Opercu l ina m i n i m a n . s p . , O p e r c u l i na dentata n . s n . : A s s i l i n a dandot ica D A V I E S , A . subspinosa D A V I E S , A . r a n i k o t i D A V I E S , A s s i l i n a s p . ; R a n i k o t h a l i a soldadensls ( V A U G H A N & C O L E ) ; Opercu l ino ides dav i e s i HASSAN and He te ros t eg ina ru ida S C H W A G E R .

The m a j o r i t y of l a rge f o r a m i n i f e r a species f r o m Gabal E l Shaghab belong to the subfami ly N u m m u l i t i n a e , and subfami ly C y c l o c l y p e i n a e . The subfami ly N u m m u l i t i n a e inc ludes the type genus N u m m u l i t e s and those of i t s neares t a l l i e s w h i c h p r e s e r v e the p l a n i s p i r a l mode of deve lopment . G e n e r i c d i s t i nc t i ons f r o m the type a r e found i n Table 1 . The subfami ly Cyc loc lype inae i s v e r y sparse ly represen ted i n the Thebes F o r m a t i o n of Gabal E l Shaghab, i t i s r ep resen ted only by genus He te ros t eg ina , al though th i s genus i s p l a n i s p i r a l i n habi t , i t s chambers a re subdivided by secondary septa in to r e c t a n g u l a r c h a m b e r l e t s .

Genera C h a r a c t e r s

N u m m u l i t e s O p e r c u l i n a A s s i l i n a Rhan iko tha l i a Ope rcu l ino ides

Shape L e n t i c u l a r , f l a t , globose

Complanate l e n t i c u l a r

L e n t i c u l a r , f l a t

l ow l e n t i c u l a r t o n e a r l y f l a t

l ow l e n t i c u l a r

F o r m Invo lu te

Evo lu te to p a r t i a l l y invo lu te

Evo lu te Invo lu te to p a r t i a l l y evolute

Invo lu te m o s t l y some tending to be e v o l u t e .

C h a m b e r tops as seen i n equa tor i a l sec t ion

Acu te angle p o s t e r i o r l y

A s i n N u m m u l i t e s

A s i n N u m m u l i t e s

B l u n t l y round g e n e r a l l y

type species as i n N u m m u l i t e s

W h o r l w a l l Single, not d i f f e ren t i a t ed cana l icu la te

A s i n N u m m u l i t e s s p i r a l canal tend to be m o r e n u m b e r s

l i k e N u m m u l i t e s

Double , i n n e r s i m p l e , ou te r c o a r s e l y cana l icu la te degenera te"

type species as i n N u m m u l i t e s

W h o r l s many v a r i a b l e

gene ra l l y few

many v a r i a b l e

g e n e r a l l y few

few to many

He igh t of c o i l s

t y p i c a l l y s l o w l y i n c r e a s i n g o r v a r i a b l e

R a p i d l y i n c r e a s i n g

t y p i c a l l y

s l o w l y i n c r e a s i n g

r a p i d l y

v a r i a b l e

r a p i d l y i n c r e a s i n g

Table 1 . The d i s t r i b u t i o n of the v a r i o u s s t r u c t u r a l fea tuers among the m o s t I m p o r t a n t genera of sub fami ly N u m m u l i t i n a e .

S U B F A M I L Y N u m m u l i t i n a e GENUS N u m m u l i t e s L A M A R C K , 1801

N u m m u l i t e s a tac icus L E Y M E R I E , 1846 B - F o r m

( p i . 2, f i g s , l a , b)

1911 N u m m u l i t e s a tac icus L E Y M E R I E . 1919 N u m m u l i t e s a tac icus L E Y M E R I E .

1925 N u m m u l i t e s a tac icus L E Y M E R I E . 1929 N u m m u l i t e s a tac icus L E Y M E R I E .

1937 N u m m u l i t e s a tac icus L E Y M E R I E .

1951 N u m m u l i t e s a tac icus L E Y M E R I E . 1967 N u m m u l i t e s a tac icus L E Y M E R I E . 1972 N u m m u l i t e s a tac icus L E Y M E R I E .

- BOUSSAC, p i . 3, f i g . 15; p i . 4 , f i g . 14 . - D O U V I L L É , p . 38, f i g . 2; p i . H I , f i g s .

1-5. - N U T T A L , p . 444, p i . 25, f i g s . 1-6. - L L U E C A , p . 102, p l . ÍV, f i g s . 2 -10 , p i .

V , f i g s . 1-5. - D A V I E S & P I N F O L D , p . 24, p i . H I , f i g s .

4 , 8 , 1 0 . - S C H A U B , p . 133, f i g s . 137-139 . - N E M K O V , p . 205, p i . 27, f i g s . 1-3. - K E N A W Y , p . 280, p l . I l l , f i g s , l a , 2a;

p l . V , f i g . l a .

The e q u a t o r i a l sec t ion shows 7 w h o r l s I n a r a d i u s of 3 . 6 m m . The w i d t h of the spacing of w h o r l s i nc reases v e r y s l o w l y t i l l the end . The septa are a r ched , i n c l i n e d , s l i g h t l y t h i c k e r a t the base . The h igh t of the chamber s i s l a r g e r than the w i d t h .

The a x i a l sec i ton i s c h a r a c t e r i z e d by r e g u l a r w h o r l s , n a r r o w s p i r a l c a v i t y , t h i c k s p i r a l l a m i n a and t h i c k m a r g i n a l c o r d . No p i l l a r s a r e obse rved . D i a m e t e r : 7 .2 m m , th ickness : 2 . 4 m m .

Occurence: T h i s species i s v e r y c o m m o n i n the upper l imes tone beds of the Thebes F o r m a t i o n at Gabal E l Shaghab. D i s t r i b u t i o n : T h i s w e l l known species o c c u r s i n the L o w e r Eocene beds i n Europe , M e d d i t e r r a n e a n and the F a r Eas t . N u t t a l de sc r ibed N . a tac icus f r o m the L a k i Ser ies and the l o w e r p a r t of the M i d d l e K h i r t h a r beds i n I n d i a .

N u m m u l i t e s g lobu lus L e y m e r i e , 1846 A - F o r m

( p i . 2, f i g . 6; p i . 4, f i g . 4)

1926 N u m m u l i t e s G u e t t a r d i D ' A R C H I A C ,

1919 N u m m u l i t e s g lobu lus L E Y M E R I E . 1929 N u m m u l i t e s g lobu lus L E Y M E R I E . 1937 N u m m u l i t e s g lobulus L E Y M E R I E . 1951 N u m m u l i t e s g lobulus L E Y M E R I E . 1967 N u m m u l i t e s g lobulus L E Y M E R I E . 1972 N u m m u l i t e s g lobu lus L E Y M E R I E .

- D O N C I E U X , p . 59, f i g s . 15-18; p i . 5, f i g s . 8 -12 .

- D O U V I L L E , p . 54, p l . 1 , f i g s . 12 -17 . - L L U E C A , P . 105, p l . V , f i g s . 6 -10 . - D A V I E S & P I N F O L D , p . 22, p l . I I I . f i g . 3 . - SCHAUB, p . 106, f i g . 4 7 - 5 1 . - N E M K O V , p . 202, p i . 26, f i g s . 1-6. - K E N A W Y , p . 278, p l . I V , f i g s , l a , b .

The e q u a t o r i a l sec t ion r evea l s a s m a l l nuc leoconch, the pro toconch i s l a r g e r the deu te roconch . The re a re 4 w h o r l s i n a r a d i u s of 1 m m . The w i d t h of the spacing of w h o r l s inc reases v e r y s l o w l y . Septa a l m o s t s t r a igh t i n t h e i r l o w e r p a r t , somewhat

bent i n t h e i r upper p a r t . T h e i r l o w e r p a r t s are somewhat t h i c k e n e d . The he igh t of the chambers l a r g e r than t h e i r w i d t h .

The a x i a l sec t ion i s c h a r a c t e r i z e d by i t s b iconvex f o r m the t h i c k s p i r a l l a m i n a , the t h i c k m a r g i n a l c o r d , w h i c h measure abbut 1/3 the s p i r a l c a v i t y , and the p i l l a r s w h i c h r u n i n bundle, f o r m i n g a l a r g e p o l a r pus tu la a t the pole of the t e s t . D i a m e t e r : 2 m m , th ickness : 1 m m .

Occurence: The r ep re sen t a t i ve s of t h i s species a re found i n l a rge number at the top beds of Gabal E l Shaghab. D i s t r i b u t i o n : D o u v i l l e r e c o r d e d th i s species f r o m the L o w e r Eocene of the A q u i t a i n , F r a n c e . L l u e c a desc r ibed th i s species f r o m the Y p r e s i a n of Spain. Davies found t h i s species i n the L o w e r Eocene beds of the Punjab Salt Range i n I n d i a . Schaub, m e n tioned t h i s species f o r m the L o w e r p a r t of the Sch l i e r en f ly sch i n S w i t z e r l a n d . N e m k o v , r eco rded th i s species f r o m the L o w e r Eocene of the Soviet U n i o n . Kenawy desc r ibed N . globulus f r o m the L o w e r Y p r e s i a n of the Thebes F o r m a t i o n at T a r a m s a sec t ion , Qena E g y p t . S t ra t ig raph ie p o s i t i o n : L o w e r Y p r e s i a n .

N u m m u l i t e s s o l i t a r i u s D E L A H A R P E , 1883 A - F o r m

(P i . 2, f i g . 7)

1883 N u m m u l i t e s s o l i t a r i a D E L A H A R P E . - p . 176, p i . 3 1 , f i g s . 18 -19 . 1951 N u m m u l i t e s s o l i t a r i u s D E L A H A R P E . - SCHAUB, p . 97-98, f i g s . 25 -28 . 1961 N u m m u l i t e s s o l i t a r i u s D E L A H A R P E . - SAID & K E R D A N Y , p . 325, t e x t f i g .

7, f i g s . 2a, b , c . 1967 N u m m u l i t e s s o l i t a r i u s D E L A H A R P E . - N E M K O V , p . 164, p i . 18, f i g s . 8 -12 . 1972 N u m m u l i t e s s o l i t a r i u s D E L A H A R P E . - K E N A W Y , p . 278, p i . H I , f i g s , l b ,

2b; p l . I V , f i g s . 2a, b .

The A x i a l sect ion: T h i s s m a l l N u m m u l i t e s i s c h a r a c t e r i z e d by i t s b iconvex f o r m , i t s r a p i d l y i n c r e a s i n g w h o r l s , i t s t h i n m a r g i n a l c o r d and by the presence of a m e d i a n tube rc l e at the pole of the t e s t .

Occurence: T h i s species i s found together w i t h N . a tac icus , N . g lobulus i n the upper p a r t of the l imes tone beds i n Gabal E l Shaghab. D i s t r i b u t i o n : T h i s species was desc r ibed by DE L A H A R P E f r o m the Esna Shale of E l Guss A b u A i d , F a r a f r a O a s i s . Schaub r e c o r d e d t h i s species f r o m the Upper Paleocene and the L o w e r Eocene of the Sch l i e r en f ly sch i n S w i t z e r l a n d . SAID & K E R D A N Y observed N . s o l i t a r i u s f r o m the upper p a r t of the Esna Shale i n F a r a f r a Oas i s . Nemkov r eco rded a l so th i s species f r o m the L o w e r Eocene of the Soviet U n i o n . K E N A W Y desc r ibed th i s species f r o m the Thebes F o r m a t i o n of T a r a m s a sect ion, Qena, N i l e V a l l e y . Age : L o w e r Y p r e s i a n .

GENUS Opercu l ina D ' O R B I G N Y , 1826

T h i s genus i s d is t inguished f r o m A s s i l i n a by the m o r e r a p i d l y opening na tu re of the s p i r e and f ewer w h o r l s .

1937 Ope rcu l ina j i w a n i D A V I E S & P I N F O L D , p . 39, p i . 5, f i g s . 11 -14 , 16 .

Tes t m e d i u m , compressed , i t measu re s about 3 .5 m m . i n d i a m e t e r and 2 . 0 m m i n t h i cknes s . I t i s composed of 3^- w h o r l s . The w h o r l s a re d iv ided up by p r o m i n e n t

f o r m of the w h o r l s r e semble a s m a l l c o i l of r o p e . A t the cen t r e , the re a re a s m a l l group of p i l l a r s wh ich m a r k s the pole of the t es t . .

I n the a x i a l sect ion, the c h i e f th ickness of the tes t i s at the po les , the p e r i p h e r ! i s subrounded. The p i l l a r s a r e m o r e concent ra ted at the p o l e . The m a r g i n a l c o r d i s t h i c k , I t measures about 1/3 the s p i r a l c a v i t y .

Occurence: T h i s species i s found toge ther w i t h N u m m u l i t e s a tac icus , N . g lobu lus , N . s o l i t a r i u s i n the Thebes F o r m a t i o n of Gabal E l Shaghab. D i s t r i b u t i o n : Opercu l ina j i w a n i was desc r ibed by D A V I E S f r o m the L o w e r Eocene of Kha i r abad l imes tone and the Pa ta la Shales, Punjab Salt Range, I n d i a . S t r a t i g r aph ie range: L o w e r Y p r e s i a n .

T h i s subspecies d i f f e r s f r o m the above species of D A V I E S by i t s l a r g e s ize , i t measures about 7.0 m m i n d i a m e t e r and 2 . 2 m m i n t h i c k n e s s .

E q u a t o r i a l sec t ion shows the presence of 4^- w h o r l s . The l a s t w h o r l s i s two t i m e s h ighe r than the p rev ious one . The n u m b e r of chamber a re 12, 18, 24, 32 i n the f o u r w h o r l s r e s p e c t i v e l y . The septa a re t h i n , r e g u l a r , n e a r l y u p r i g h t f o r the f i r s t t w o -t h i r d s of t h e i r height , then r e c u r v e d i n the upper t h i r d .

Occurence: T h i s subspecies i s found toge ther w i t h Ope rcu l ina j i w a n i i n the Thebes F o r m a t i o n of Gabal E l Shaghab. Age: L o w e r Y p r e s i a n .

O p e r c u l i n a j i w a n i D A V I E S 1937 ( p l . 1 , f i g s . 1 , 2; p i . 3, f i g . 2)

granula ted septa, and s p i r a l channe l . The

O p e r c u l i n a j i w a n i D A V I E S grand i s n . subsp. ( p l . 1 , f i g . 3; p i . 2, f i g . 2; p i . 3, f i g . 1 . p i . 4 . f i g . 2 . )

O p e r c u l i n a pa ta lens i s D A V I E S , 1937 ( P I . 2, f i g . 9)

1937 O p e r c u l i n a pa ta lens is D A V I E S , p . 38, p i . 5, f i g s . 6, 17-19, 2 6 .

Tes t l a r g e , complanate , w i t h p r o m i n e n t umbo , a s m a l l c l u s t e r of g ranu les appear 64

at the p o l e . D i a m e t e r about 6 m m . The w h o r l s inc rease r e g u l a r l y . T h e r e a re 4 - 5 w h o r l s , the ra te of inc rease of w h o r l i n g i s not v e r y h i g h , the l a s t w h o r l i s on ly about tw ice as h igh as the p r eced ing w h o r l . The septa a re t h i n , and s l i g h t l y c u r v e d th roughout .

The a x i a l s ec t ion i s c h a r a c t e r i z e d by the t h i c k m a r g i n a l c o r d and the t h i c k s p i r a l l a m i n a .

Opercu l ina m i n i m a n . sp . ( p l . 1 , f i g . 16)

Tes t s m a l l , c o m p r e s s e d , t h i n I t s d i a m e t e r i s about 1.8 m m . , i t s th ickness i s 0 . 2 m m . T h e r e a r e 4 c o i l s , the number of c h a m b e r s i n the c o i l i s 13 . The septa a r e m a r k e d e x t e r n a l l y by costae and r a t h e r f ine g r anu l e s , they a re n e a r l y s t r a i g h t . The he ight of the chamber s i s m u c h l a r g e r than t h e i r w i d t h ; the h e i g h t / w i d t h r a t i o be ing 4 : 1 .

T h i s species appears i n cons iderab le n u m b e r s i n the upper l i m e s t o n e of the Thebes F o r m a t i o n of Gabal E l Shaghab.

R e m a r k s : T h i s species I s c l o se ly re l a t ed to O . m a r i a n n e n s i s V A U G H A N d e s c r i b e d f r o m the Eocene beds of Oca la l imes tone , F l o r i d a , i n i t s de l ica te tes t and i t s s m a l l n u m b e r of chamber s ; i t i s d i s t ingu ished f r o m the l a t t e r , by i t s s t r a i g h t septa, f ine g ranu les and hav ing no c o n i c a l tuberc le at the cen te r of the t e s t .

Opercu l ina dentata n . sp . ( p l . 1 , f i g s . 9, 17)

Tes t m e d i u m , c o m p r e s s e d , i t s d i a m e t e r i s 3 .0 m m and i t s th ickness i s 0 .3 m m . The tes t i s about the same th ickness ; sur face smooth , composed of 3^ w h o r l s , g r a dua l ly i n c r e a s i n g . The p e r i p h e r y i s acute s e r r a t e d . The l a s t w h o r l con ta in ing 22 c h a m b e r s . The he ight of the chamber i s l a r g e r than t h e i r w i d t h . The septa a r e curved convexly o u t w a r d s .

T h i s species i s c h a r a c t e r i z e d by i t s s e r r a t e d p e r i p h e r y .

Occurence: T h i s species i s found i n cons iderab le n u m b e r i n the upper l i m e s t o n e of the Thebes F o r m a t i o n of Gabal E l Shaghab.

Genus A s s i l i n a D ' O R B I G N Y , 1926

T h i s genus i s d i s t i ngu i shed f r o m N u m m u l i t e s by the absence of septal f i l a m e n t s . The w h o r l s may o r m a y not be f u l l y enveloping, bu t they a re c lo se ly e m b r a c i n g , tha t no space i s l e f t between t h e m . Owing to the absence i n A s s i l i n a of septal f i l a m e n t s , the i n n e r w h o r l s and t h e i r septa are often c l e a r l y d i s t ingu i shab le on the surface of the t e s t .

A s s i l i n a dandotica D A V I E S 1937 ( p l . 1 , f i g s . 7, 8; p i . 2, f i g s . 5, 8)

1937. A s s i l i n a dandot ica D A V I E S P-28, p i . 4 , f i g s . 1 - 3 , 6 - 8 . Tes t m e d i u m , d i s c o i d , w i t h subrounded p e r i p h e r y ; I t s d i a m e t e r measures 3 .0 m m and th ickness Is 1.2 m m . The surface i s covered w i t h r e g u l a r l y d i s t r i b u t e d g r a n u l e s , s p i r a l l y a r r anged ; they a re s m a l l near the p e r i p h e r y , w h e r e they indica te the m a r g i n a l c o r d and the septa; but they are c o a r s e r over the m i d d l e p a r t of the t e s t .

The e q u a t o r i a l sec t ions shows 4 w h o r l s i n a r a d i u s of 1.5 m m . The septa a re f o r the m o s t p a r t s t r a i g h t , except i n the u p p e r m o s t p a r t s l i g h t l y r e c u r v e d . The he ight of the c h a m b e r s i s m u c h l a r g e r than t h e i r w i d t h , the h e i g h t / w i d t h r a t i o be ing 3 : 1 . They a re 10, 17, 22, 26 chambers i n the fou r w h o r l s r e s p e c t i v e l y .

Occurence: T h i s species c h a r a c t e r i s e s the u p p e r m o s t beds of Gabal E l Shaghab. D i s t r i b u t i o n : D A V I E S r e c o r d e d t h i s species f r o m the L o w e r Eocene of the Punjab Salt Range, as w e l l as f r o m the L o w e r Eocene of the R a n i k o t beds, I n d i a . S t r a t i g r aph i e p o s i t i o n : L o w e r Y p r e s i a n .

A s s i l i n a r a n i k o t N U T T A L , 1926 ( p l . 1 , f i g s . 4 , 5, 6; p i . 3, f i g . 4)

1926 A s s i l i n a r a n i k o t i N U T T A L , p . 117, p i . 10, f i g s . 7 - 1 1 .

T e s t s m a i l , l e n t i c u l a r to g l o b u l a r , w i t h sharp b o a r d e r . A v e r a g e d i a m e t e r = 2 . 7 m m and the average th ickness = 0 . 7 m m . E x t e r n a l l y the o rnamen ta t i on cons is t s of p r o m i n e n t g r a n u l e s . The g ranu les i n the cen t re a r e v e r y s t r o n g and often c lu s t e r ed t oge the r . The l a s t w h o r l I s f requen t ly devo id of g r a n u l e s .

The e q u a t o r i a l sec t ion shows 3 w h o r l s i n a r a d i u s of 1.3 m m . The septa a re gen t ly c u r v e d . The chamber s a re thus a l m o s t r e c t a n g u l a r i n shape, and about t w i c e as h igh as l o n g .

Occurence: A . r a n i k o t i appears i n cons ide rab le n u m b e r i n the Thebes F o r m a t i o n of Gabal E l Shaghab. D i s t r i b u t i o n : T h i s species was de sc r ibed by N u t t a l f r o m the Upper R a n i k o t Ser ies ( L o w e r Eocene) , I n d i a . Age : Y p r e s i a n .

A s s i l i n a subsplnosa D A V I E S 1937 ( p l . 1 , f i g . 13; p i . 2, f i g . 4 ; p i . 3, f i g . 3)

1937 A s s i l i n a subsplnosa D A V I E S , p . 33, p i . 4 , f ig3. 19, 20, 23 -26 .

Tes t m e d i u m complanate , i nvo lu t e , composed of 3 c o i l s . The surface i s covered w i t h c lose set of g ranules c o v e r i n g the whole c e n t r a l p a r t of the t e s t . The g ranu les a re e i t h e r i so l a t ed o r combined in to a k i n d of s p i r a l band . The re i s a l a r g e r median tuberc le at the pole of the t e s t . D i a m e t e r : 3 .8 m m ; th ickness : 0 . 6 . m m .

The e q u a t o r i a l sec t ion shows a d i s t i n c t l y m o r e t i g h t l y co i led s p i r e . The septa a r e gene ra l l y n e a r l y spaced, s t r a i g h t . The chambers a re about twice as h igh as l o n g .

The a x i a l s ec t ion shows the acute p e r i p h e r y , the enveloping w h o r l s and the d i s t i n c t c o a r s e r g r a n u l e s .

Occurence: T h i s species i s v e r y c o m m o n i n the Thebes F o r m a t i o n of Gabal E l Shaghab, appear ing i n company w i t h N u m m u l i t e s a t ac i cus , N . g lobulus , N . s o l i t a r i u s ; Ope rcu l ina j i w a n i and A s s i l i n a dandot ica .

D i s t r i b u t i o n : D A V I E S found t h i s species f r o m the u p p e r m o s t Ran iko t beds at T h a i and f r o m v a r i o u s l eve l s i n the Salt Range, I n d i a . S t r a t ig raph ie range: L o w e r Y p r e s i a n .

A s s i l i n a s p . ( p l . 1 , f i g s . 14, 15)

Tes t s m a l l , t y p i c a l l y w i t h in f l a t ed c e n t r a l p a r t , w i t h keeled b o r d e r . Ave rage d i a m e t e r = 1.3 m m ; average th ickness = 0 .3 m m . E x t e r n a l l y the surface i s s m o o t h . The l a s t w h o r l i s observed , devoid of g ranu les and the r i b s , w h i c h stand out on the ou te r surface , co r r e spond w i t h the septa of the i n t e r n a l s t r u c t u r e .

T h i s species appears to be s i m i l a r w i t h A s s i l i n a n i l i , o r A . m i n i m a r e c o r d e d by D E L A H A R P E (1883) f r o m Gabal T e r near Esna, Upper Egypt , but d i f f e r s f r o m them by the smooth surface and the in f l a t ed c e n t r a l p a r t .

Occurence: T h i s species appears i n cons ide rab le n u m b e r i n the upper l i m e s t o n e beds of Gabal E l Shaghab, Upper E g y p t .

GENUS R a n i k o t h a l i a C A U D R I , 1944

I n 1944 C A U D R I e rec ted the genus R a n i k o t h a l i a f o r the group of Car ibbean and I n d ian N u m m u l i t e s l i k e species w h i c h a re c h a r a c t e r i z e d by the " b l u n t l y rounded c h a m be r tops I n h o r i z o n t a l sec t ion and the th ickness of the c o a r s e l y gutted supp lementa ry skele ton as compared w i t h the m a j o r i t y of o ther N u m m u l i t e s . " The type species of Ran iko tha l i a C A U D R I i s N u m m u l i t e s n u t t a l l i D A V I E S .

Ran iko tha l i a soldadensis ( V A U G H A N and C O L E , 1941) ( p l . 4 , f i g . 3)

1941 M i s c e l l a n e a soldadensis V A U G H A N and C O L E , p . 36, p i . 4, f i g . 8 , 9 . 1944 R a n i k o t h a l i a soldadensis ( V A U G H A N and C O L E ) . - C a u d r i , p . 23, p i . 4 , f i g .

19, p i . 5, f i g . 24, 26. 1960 R a n i k o t h a l i a soldadensis ( V A U G H A N and C O L E ) . - DROOGER, p . 312, p i . 5,

f i g . 1-14;

Tes t much f la t tened , w i t h r ough ly p a r a l l e l s ides , modera te i n s ize , be ing 4 to 4 . 5 m m i n d i a m e t e r and 0 .6 m m i n t h i c k n e s s . I t cons i s t s of 4 r a t h e r r a p i d l y w i d e n i n g w h o r l s . Surface gene ra l l y s m o o t h . The e x t e r n a l surface of the m a r g i n a l c o r d i s f i s su red by many anas tomos ing g rooves , w h i c h leave i r r e g u l a r l y elongated i s l ands i n be tween .

Occurence: T h i s new species i s r e c o r d e d f o r the f i r s t t i m e i n the L o w e r Eocene of Gabal E l Shaghab. D i s t r i b u t i o n : T h i s species was desc r ibed by V A U G H A N & C O L E f r o m the L o w e r Eocene of the Soldado Rocks , T r i n i d a d .

GENUS Gpercu l ino ides H A N Z A W A 1935

Many au thors have quest ioned the exis tance of t h i s genus, and some of the t h e m have cons idered as a subgenus of the genus N u m m u l i t e s .

SACHS (1957) assigned to the genus Opercu l ino ides a n u m b e r of n u m m u l i t e s species descr ibed by M . D E C I Z A N C O U R T (1948; 1951), designated by h e r as c o r d n u m m u l i t e s " N u m m u l i t e s c o r d e l e e s " . However SACHS has not g i v e n no diagnosis of t h i s genus, n e i t h e r has he defined the d i f ference between t h i s genus and the genus N u m m u l i t e s .

B I E D A (1963) ment ioned tha t the genus Ope rcu l ino ides i s s i m i l a r to some species of n u m m u l i t e s , namely those w i t h a loose w h o r l s , however he found that there i s a d i s t i n c t d i f fe rence between the f o r m e r and the l a t t e r . I n the genus Opercu l ino ides , the nucleoeonch i s of the nephro lep id ine type (the deuteroconch i s l a r g e r than the p ro toconch , and p a r t l y embraces i t ) . B I E D A concluded that the s t r a t i g r a p h i e range of genus Opercu l ino ides i n the Carpa th ian F l y s c h , i n A m e r i c a and i n the T a t r a Eocene begins i n the Upper Eocene . Howeve r SACHS (1957) r e c o r d e d Opercu l ino ides b e r m u d e z i i n the Paleocene of c e n t r a l A m e r i c a . The openion of the p r e sen t author i s that the genus Opercu l ino ides belongs to a t r a n s i t i o n a l genus between N u m m u l i t e s and Ope rcu l ina w i t h invo lu te tes t and r a p i d l y i n c r e a s i n g whor ls , . (Table 1 . ) . The p re sen t au thor observed i n the studied sec t ion some spec imens , w h i c h agree p e r f e c t l y w i t h HASSAN (1953) f i g u r e s iden t i f i ed as Opercu l ino ides d a v i e s i .

Opercu l ino ides d a v i e s i HASSAN, 1953 ( p i . 2, f i g . 3a, 3b; p i . 4 , f i g . 1)

1953 Opercu l ino ides d a v i e s i HASSAN, p . 11 , p l . 1 , f i g . 3 .

Tes t s m a l l , hav ing an average d i a m e t e r of 1.5 m m and an average th ickness of 0 .3 m m . The edge i s s h a r f . The e q u a t o r i a l sec t ion shows 2* w h o r l s . The s p i r a l l a m i n a i s r e g u l a r and t h i n . The w h o r l i n g i s l ax e x p e c i a l l y the l a s t w h o r l w h i c h i s th ree t i m e s h i g h e r than the p receed ing one. The septa a re numerous , v e r t i c a l and curve only nea r the r o o f of the c h a m b e r . The chambers a re much h i g h e r than w i d e .

The a x i a l sec t ion i s c h a r a c t e r i z e d by i t s t h i n m a r g i n a l c o r d , t h i n s p i r a l l a m i n a and a s l i g h t l y p r o m i n e n t p o l a r at the pole of the t e s t .

Occurence: T h i s species has been found i n the upper l imes tone beds of the Thebes F o r m a t i o n a t Gabal E l Shaghab. D i s t r i b u t i o n : HASSAN (1953) desc r ibed t h i s species f r o m the L o w e r L i b y a n r o c k s i n Kharga Oasis and gave i t a L o w e r Paleocene age. Age : L o w e r Y p r e s i a n .

F A M I L Y N u m m u l i t i d a e S U B F A M I L Y Cyc loc lype inae

GENUS Hete ros teg ina D ' O R B I G N Y , 1826

He te ros t eg ina r u i d a SCHWAGER, 1883. ( p l . 1 ; f i g . 12)

1883 Hete ros teg ina r u i d a SCHWAGER, p . 145, p l . 29, flg. 6a -6b .

1937 Hete ros teg ina c f . r u i d a SCHWAGER. - D A V I E S & P I N F O L D , p . 52, p i . 5, f i g . 2 1 .

Tes t s m a l l , d i s c o i d a l ; e a r l i e r p a r t i n v o l u t e , r a p i d l y becoming evo lu te , composed of 2 w h o r l s ; the second w h o r l has about 18 c h a m b e r s . The septa a re h i g h e r developed i n the l a s t w h o r l . The f i r s t of w h i c h conta ins about 6 c h a m b e r l e t s . The spec imens have p r o m i n e n t and s t r o n g l y g ranu la ted p o l e s .

Occurence: T h i s species i s observed toge ther w i t h the o ther O p e r c u l i n a and A s s i l i n a species i n the upper n u m m u l i t i c l imes tone of the Thebes F o r m a t i o n . D i s t r i b u t i o n : SCHWAGER (1883) desc r ibed th i s species f r o m the upper beds of E l Guss A b u Said, F a r a f r a O a s i s . T h i s species i s s i m i l a r t o the Ind ian spec imens , i l l u s t r a t e d by D A V I E S (1937) f r o m the Sakesar l imes tone of the Punjab Salt Range .

DISCUSSION

The f o r a m i n i f e r a assemblage l i s t e d above, i s i n favour o f L o w e r Y p r e s i a n age. I t can be equated w i t h the N u m m u l i t e s s o l i t a r i u s Zone of the L o w e r Y p r e s i a n age in t roduced by K E N A W Y (1972) f r o m the Thebes F o r m a t i o n of the T a r a m s a sec t ion , Qena a r e a . They can a lso be c o r r e l a t e d w i t h the Kha i rabad l imes tone and the Pa t a l a Shale (of E a r l y Eocene age) of the Punjab Salt Range of I n d i a . Howeve r , they can never be equated w i t h the l o w e r m o s t R a n i k o t beds of the E a r l y Paleocene age as ment ioned before by HASSAN (1953). The presence of N u m m u l i t e s a tac icus and N . g lobulus ( recorded by S C H A U B , 1951, f r o m the L o w e r Y p r e s i a n of the S c h l i e r e n f l y s c h i n Swi tzer land) and of R a n i k o t h a l i a soldadensis desc r ibed f r o m the L o w e r Eocene of the Soldado Rocks , T r i n i d a d , c l e a r l y c o n f i r m s the L o w e r Y p r e s i a n age g iven f o r these r o c k s .

Since the w o r k o f D ' A R C H I A C & H A I M E (1853), au thors have t r i e d to compare the fauna of the F a r Eas t w i t h the n u m m u l i t i c f o r m a t i o n s of the M e d i t e r r a n e a n a r e a . Rap id changes of facies and gaps i n depos i t ion , compl i ca t e these c o r r e l a t i o n s . D A V I E S (1949) suggested that a m a r i n e connect ion was p r e s e n t between Wes t and Eas t Ind ies ( A n t i l l e s ) i n basa l T e r t i a r y t i m e s , before the A m e r i c a s w e r e d r i f t e d f r o m Europe and A f r i c a . He a sked ,whe the r m i s c o m m u n i c a t i o n was ac ross N o r t h A f r c i a to the Ind ian sea o r the l i n e of c o m m u n i c a t i o n pass southwards round the coast of A f r i c a ?

The r e s u l t of the p r e sen t study and the resemblane of the l a r g e r f o r a m i n i f e r a l assemblage I n the E a r l y Eocene t i m e of Gabal E l Shaghab and that of Kha i r abad l imes tone and Pata la Shales i n the Punjab Salt Range i n Ind ia , suppor t the idea tha t a w e s t w a r d extending a r m of the Ind ian Sea t r a v e r s e d the Sahara r e g i o n of N o r t h A f r i c a i n the E a r l y T e r t i a r y t i m e .

K E N A W Y , A . L : Ujabb al6Óeocén-kori nagyforaminiferák Esna környékéről (Felső Egyiptom)

Szerző a felsőegyiptomi Esna környékéről (Gabal E l Shaghab) 18 n a g y f o r a m i n i f e r a fa j t ír t l e . K o r u k alsó ypréz i , és Egyiptomból e lőször kerülnek le í rás ra . I n d i a i a d a tokka l egybevetve (DÁRIES & P I N F E L D , 1937) s z e r z ő feltételezi , hogy az e g y k o r i i n d i a i tengerrész összeköttetésben állhatott É-Afrika szahara i területével .

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P L A T E 2 .

1: N u m m u l i t e s a tac icus L E Y M E R I E - B - f o r m - a = a x i a l sec t ion (x 20), b = e q u a t o r i a l s e c t i o n .

2: O p e r c u l i n a j i w a n i D A V I E S g r a n d i s n . ssp . - e q u a t o r i a l sec t ion (x 15) 3: Opercu l ino ides dav i e s i HASSAN - a = a x i a l sec t ion , b = e q u a t o r i a l s ec t ion

(x 20) 4: A s s i l i n a subsplnosa D A V I E S - e q u a t o r i a l sec t ion (x 20) 5. 8: A s s i l i n a dandot ica D A V I E S - e q u a t o r i a l sec t ion (x 15) 6. N u m m u l i t e s g lobulus L E Y M E R I E - A - F o r m - e q u a t o r i a l sec t ion (x 15) 7. N u m m u l i t e s s o l i t a r i u s D E L A H A R P E - A - F o r m - a x i a l sec t ion (x 20) 9: Ope rcu l ina pa ta lans i s D A V I E S - e q u a t o r i a l sec t ion (x 10)

P L A T E 3 .

1 . P h o t o m i c r o g r a p h of a t h i n sec t ion showing a x i a l sec t ion i n O p e r c u l i n a j i w a n i D A V I E S g r a n d i s n . s sp . (x 20)

2 . P h o t o m i c r o g r a p h of a t h i n sec t ion showing a x i a l sec t ion i n O p e r c u l i n a j i w a n i D A V I E S (x 20)

3 . P h o t o m i c r o g r a p h of a t h i n sec t ion showing a x i a l sect ions i n A s s i l i n a subsplnosa D A V I E S (x 20)

4 . P h o t o m i c r o g r a p h of a t h i n sec t ion showing e q u a t o r i a l sec t ions i n A s s i l i n a r a n i k o t i N U T T A L (x 20)

I V . TÁBLA P L A T E I V

P L A T E 4 .

1 . P h o t o m i c r o g r a p h of a t h i n s e c t i o n showing a x i a l sect ions i n Opercu l ino ides dav i e s i HASSAN (x 30)

2 . P h o t o m i c r o g r a p h of a t h i n s e c t i o n showing a x i a l sec t ion i n O p e r c u l i n a j i w a n i D A V I E S g r a n i d s n . ssp . (x 20)

3 . P h o t o m i c r o g r a p h of a t h i n s e c t i o n showing a x i a l sec t ion i n R a n i k o t h a l i a soldadensis ( V A U G H A N Cole) (x 20)

4 . P h o t o m i c r o g r a p h of a t h i n s e c t i o n showing a x i a l sect ions i n N u m m u l i t e s g lobulus L E Y M E R I E (x 30)