->->4 UPPER CRETACEOUS-LOWER TERTIARY FOR AMINIFER A 



The species is morphologically similar to G. uncinata uncinata (Bolli) from which it 

 is distinguished by its radial, depressed intercameral sutures, which are curved 

 and depressed in G. uncinata, its roughly spinose ventral side, its less tightly coiled 

 test, compressed early part and inflated later part, and its wider umbilicus. Globo- 

 rotalia uncinata was only recorded from the lower part of the Middle Paleocene while 

 G. perclara ranges throughout the whole Paleocene. Berggren (1960a) stated that 

 further study may reveal these two forms to be conspecific, but the present study 

 strongly substantiates their separate identity. 



Globorotalia perclara probably evolved from G. trinidadensis Bolli by the reduction 

 in the size of test, the flattening of the early part and the development of the surface 

 rugosity although no direct evidence was recorded. On the other hand, it is believed 

 to have evolved into G. sibaiyaensis sp. nov. by the further reduction in the size of 

 test, and the development of an entire, heavily spinose surface. The morphological 

 features and stratigraphical ranges of these species support this suggestion. 



Hypotype. P. 45620. 



Horizon and locality. Figured specimen, from sample No. 35, Gebel Owaina 

 section. 



Stratigraphical range. The species was first described by Loeblich & Tappan 

 (1957a) from the Danian Brightseat formation of Alabama and was reported to range 

 throughout the Paleocene and the Lower Eocene of the Gulf and Atlantic Coastal 

 Plains, U.S.A. However, the Nanafalia formation of Alabama, which they consider- 

 ed as Lower Eocene, was regarded by Bramlette & Sullivan (1961) and Gartner & Hay 

 (1962) to belong to the Paleocene. The species was also recorded by Olsson (i960) 

 from the Hornerstown formation of New Jersey and was observed in the Noxontown 

 fauna by the same author. 



In the Esna-Idfu region, G. perclara ranges throughout most of the Paleocene, 

 being common to flood in the Lower and Middle Paleocene, and rare in the Upper 

 Paleocene. It dies out completely in the lower part of the G. aequa-G. esnaensis 

 Subzone. 



Globorotalia pseudobulloides (Plummer) 



(PL 18, figs. 30-c) 



1926 Globigerina pseudobulloides Plummer : 133-134, pi- 8, figs. ga-c. 



19376 Globigerina pseudobulloides Plummer ; Glaessner : 382, pi. 4, figs. ^ia-c. 



1940 Globigerina pseudobulloides Plummer ; Cushman : 72, pi. 12, figs. 16a, b. 



1942 Globigerina pseudobulloides Plummer ; Cushman & Todd : 43, pi. 8, figs, 3, 4. 



1949 Globorotalia (Globorotalia) compressa (Plummer) ; Cushman & Bermudez : 34-35, 



pi. 6, figs. 19-21. 

 1949 Globigerina cf. pseudobulloides Plummer ; Cushman & Stone : 57, pi. 10, fig. 15. 

 1951 Globigerina pseudobulloides Plummer : Cushman : 60, pi. 17, figs. 7, 8. 

 x 953 Globigerina compressa Plummer var. compressa Plummer ; Subbotina (pars) : 55, 



pi. 2, figs. 3«-5c, ? figs, la-c, non figs. 6a-c. 

 1953 Globigerina compressa Plummer var. pseudobulloides Plummer ; Subbotina : 57, pi. 2, 



figs, ya-i^c. 



