130 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFER A 



confused this form with various other species and thus confused its range which she 

 stated to be Cenomanian-Maestrichtian. However, all reliable records show that 

 the present subspecies ranges throughout the Upper Campanian-Middle Maestrich- 

 tian only. In the Esna-Idfu region, G. rosetta rosetta (Carsey) occurs as an abundant 

 form in the Lower Maestrichtian G. fornicata Zone, decreasing gradually upwards in 

 the section and becoming common or rare in the lower part of the overlying G. 

 gansseri Zone, where it dies out completely. 



Globotruncana sharawnaensis sp. nov. 

 (PI. 12, figs. ^a-d) 



Diagnosis. A Globotruncana with large, spiroconvex test, single keel in early part 

 becoming double in last chamber, depressed ventral sutures and delicately papillose 

 surface on ventral side. 



Description. Test large, coiled in a high trochospire ; dorsal side broadly 

 convex and highly arched, ventral side almost flat, very slightly raised and weakly 

 inflated ; equatorial periphery subcircular, slightly lobate, with a single, well- 

 developed, beaded keel on the early chambers of the last whorl and two distinct, 

 closely spaced, beaded keels on the last chamber ; axial periphery angular in the 

 early part, truncate on the last chamber, where the two marginal keels are very close 

 and enclose a very narrow peripheral band ; chambers on the dorsal side 21, arranged 

 in 3 dextrally coiled whorls and increase slowly in size ; the initial chambers are small, 

 inflated, globigerine, and are followed by roughly quadrangular to crescentic cham- 

 bers ; the last whorl is composed of 6\, large chambers, which are generally crescentic 

 to quadrilateral ; on the ventral side the chambers are 6|, roughly ovoid to somewhat 

 quadrangular, weakly inflated, slightly overlapping, and increase slowly in size; 

 sutures on the dorsal side are curved, raised and beaded in the early part and short, 

 very slightly curved to almost straight, raised and beaded in the later ; on the ventral 

 side the sutures are almost straight, radial and depressed in the early part, slightly 

 curved forward and depressed later ; umbilicus polygonal in outline, wide, deep, 

 surrounded by slightly raised, delicately beaded ridges and 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 

 smooth on the dorsal side, papillose on the ventral, with the papillae fading out 

 gradually on the last two chambers. 



Dimensions of holotype. 



Maximum diameter = 0-50 mm. 



Minimum diameter = 0-40 mm. 



Thickness = 0-28 mm. 



Main variation. 



1. Chambers 18-22, arranged in 3-3 1 whorls, generally dextrally coiled. 



2. The last whorl is composed of 6-7 chambers. 



