IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 95 



In the Esna-Idfu region, G. contusa patelliformis occurs in the basal part of the 

 Middle Maestrichtian G. gansseri Zone, where it increases gradually upwards in the 

 section to flood the middle and upper parts of this zone and then fades out gradually 

 in the overlying G. esnehensis Zone before dying out completely in the upper part of 

 the latter zone. 



Globotruncana contusa scutilla Gandolfi 



1955 Globotruncana {Globotruncana) contusa (Cushman) scutilla Gandolfi : 54, pi. 4, figs. la-c. 



Remarks. A few specimens referable to the present subspecies were recorded 

 from the G. fornicata Zone. Morphologically they appear to be so closely similar 

 to G. contusa patelliformis that they could be considered small forms of it, despite the 

 great difference in size. However, as it was only recorded from the G. fornicata 

 Zone of the sections studied, and was stated by Gandolfi (1955) to appear in north- 

 eastern Colombia much earlier in the succession than G. contusa patelliformis (the 

 former appears in the Coniacian while the latter appears in what he considered 

 Campanian), it was found advisable to treat it separately. 



G. contusa scutilla (if treated separately from G. contusa patelliformis) is believed 

 to have evolved from G. fornicata fornicata (Plummer) into G. contusa patelliformis 

 Gandolfi. 



Hypotype. P.45523. 



Stratigraphical range. Gandolfi (1955) recorded the present subspecies as 

 ranging throughout the upper part of the Manaure shale and the basal part of the 

 Colon shale of northeastern Colombia, which he considered as Coniacian-Lower 

 Campanian. However, as previously mentioned, all the Colon shale is probably 

 Maestrichtian in age. 



In the Esna-Idfu region G. contusa scutilla occurs as common to rare in the 

 Lower Maestrichtian G. fornicata Zone only. 



Globotruncana contusa witwickae subsp. nov. 



(PI. 7, figs, la-c) 



Diagnosis. A Globotruncana contusa (Cushman) with much lower spire, less 

 plicated surface and less elongated chambers on dorsal side. 



Description. Test large, robust, spiroconvex, coiled in a relatively high trocho- 

 spire ; dorsal side moderately convex, gently plicate and undulate ; ventral side 

 almost flat and weakly inflated ; equatorial periphery bluntly polygonal, with two 

 well-developed, heavily beaded, marginal keels which enclose a narrow, slightly 

 inclined peripheral band and tend to weaken towards the last chamber where the 

 ventral keel is completely reduced ; axial periphery subangular, subtruncate ; 

 chambers on the dorsal side 17, arranged in 3 dextrally coiled whorls ; initial chambers 

 very small, globular, weakly inflated, increasing very slowly in size, followed by much 



