IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 105 



Horizon and locality. Figured specimens, PI. 13, figs 3«-c from sample No. 

 16, W. El-Sharawna section, figs, ^a-c, from sample No. 14, Gebel A 314 section ; 

 PI. 14, figs. 6a-c, from sample No. 4, Abou Saboun section. 



Stratigraphical range. Gandolfi (1955) described this subspecies from the 

 Colon shale of northeastern Colombia where he considered its range as Campanian- 

 basal Maestrichtian. 



In the Esna-Idfu region, G. fornicata cesarensis floods the Lower Maestrichtian 

 G. fornicata Zone, fades out gradually upwards in the section and occurs as a rare 

 form in the basal part of the overlying G. gansseri Zone where it dies out completely. 



Globotruncana fornicata fornicata Plummer 

 (PI. 13, figs. 5«-c, 6 ; PI. 14, figs. la-c) 



1931 Globotruncana fornicata Plummer : 198, pi. 13, figs. /\a-c, 5, 6. 



1951 Globotruncana fornicata Plummer ; Drooger : 7, pi. 1, figs. qa-c. 



J 953 Globotruncana fornicata Plummer ; Hagn : 98, pi. 8, figs. 8a-c, text-figs. 22, 23. 



1953 Globotruncana fornicata Plummer ; Subbotina : 184-185, pi. 8, figs. 3«-c, ? \a-y. 



1955 Globotruncana {Globotruncana) fornicata plummerae Gandolfi : 42, pi. 2, figs. $a-c, ? ^a-c. 



1961 Globotruncana fornicata Plummer ; Graham & Clark : 112, pi. 5, figs. 10a — c. 



1962 Globotruncana (Globotruncana) fornicata Plummer ; Pessagno : 362, pi. 4, figs. 4, 5, 11. 



1963 Globotruncana fornicata Plummer ; Lehmann : 148, pi. 7, figs. ia-2C ; ? ^a-^c ; text- 

 figs, iv, w ; 3«, r, t 



Description. (Specimen, PI. 13, figs. 5«-c.) Test large, biconvex, coiled in a 

 low trochospire ; dorsal side slightly convex, moderately inflated, ventral side 

 slightly more inflated and relatively protruding ; equatorial periphery ovoid, 

 slightly lobate, with two well-developed, delicately beaded diverging keels ; axial 

 periphery truncate ; chambers on the dorsal side 17, arranged in 3 dextrally coiled 

 whorls ; initial chambers very small, almost indistinct, globigerine, weakly inflated, 

 increasing slowly in size ; they are followed by relatively larger, globular, slightly 

 inflated chambers which also increase slowly in size till the beginning of the last 

 whorl where they start to change their shape and rate of growth ; the last whorl 

 constitutes most of the test and is composed of 4J large, long, narrow inflated, 

 slightly folded, highly curved crescentic chambers ; on the ventral side the chambers 

 are 4, kidney-shaped, moderately inflated and strongly overlapping ; sutures on the 

 dorsal side are curved, raised, delicately beaded, tending to merge into relatively 

 sharp depressions from the periphery inwards towards the preceding whorl (as in 

 Plummer's description) ; on the ventral side the sutures are strongly curved forward, 

 slightly raised and delicately beaded ; umbilicus roughly rhomboidal in outline, 

 wide, deep, bordered by slightly raised delicately beaded ridges, covered by complex 

 tegilla of which remnants are still preserved ; primary apertures interiomarginal, 

 umbilical ; tegilla, with accessory apertures, only poorly preserved ; wall calcareous, 

 perforate except for the imperforate keels, peripheral band and tegilla ; surface 

 delicately papillose in the early part and on the ventral side, becoming smooth 

 towards the last chamber ; the two keels enclose a relatively wide, depressed, 

 slightly inclined peripheral band which is relatively narrow at the posterior part of 

 test but widens out anteriorly as the keels diverge. 



