ib., UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



Paleocene fauna in holes in the hard ground on top of the Md of Holland and Den- 

 mark, and to repeated attempts by Hofker to equate the type Maestrichtian with the 

 type Danian, and to build bioseries representing continuous evolution from the 

 Upper Cretaceous to the basal Tertiary. 



The evolutionary trends suggested by Hofker (1960^, i) for G. daubjergensis can 

 be summarized as follows : 



1. A gradual increase in the size of test and a decrease in the density of spines 



on the walls of the last-formed chambers upwards in the section. 



2. The development of small openings on the dorsal side from the Middle Danian 



onwards ; these become more frequent higher in the section. 



3. The increase in the size of the last-formed chambers, which may, in the 



highest levels of the Danian and in the overlying greensands, cover the 

 whole umbilical region and the visible aperture (Catapsydrax character) . 



This clearly shows that Hofker confused G. daubjergensis with forms such as 

 G. kozlowskii ; the former was not reported to cross the Danian-Middle Paleocene 

 boundary, while the latter was reported from the middle and Upper Paleocene 

 where it was said to display both the Globigerinoides and Catapsydrax characters 

 assigned by Hofker to G. daubjergensis in its later stages of development. However, 

 this evolutionary series was partially substantiated by Berggren (1962) in his study 

 of specimens from southern Scandinavia, but it is probable that he had also confused 

 G. daujergensis with the early stages of G. kozlowskii. 



In the Esna-Idfu region, it was not possible to follow the evolutionary development 

 of the species as suggested by Hofker, because the Lower and Middle Danian are 

 missing. However, the specimens studied show a general tendency to increase the 

 size of test and to reduce the surface rugosity on the chambers of the last whorl. 

 Hofker (1960^, i) greatly overemphasized the value of these continuous morphological 

 changes in G. daubjergensis as tools in working out the detailed stratigraphy of the 

 Danian stage. Without belittling these observations, it has to be stated that the 

 distinct stages, mentioned by Hofker, are most probably distinct species, and that in 

 a single species population, a wide range of variation was observed. 



The physical and biological break at the base of the Danian made it difficult to 

 trace the ancestral stock from which G. daubjergensis had evolved. This might have 

 been any of the apparently similar Rugoglobigerina or Hedbergella forms which flood 

 the Maestrichtian rocks below. Again, it is believed that G. daubjergensis evolved 

 into G. kozlowskii since all transitional stages between them have been recorded. On 

 the other hand, G. daubjergensis is believed to be related to the similarly trocho- 

 spirally coiled forms, G. chascanona Loeblich & Tappan and G. spiralis Bolli, although 

 no direct evidence was recorded. 



Hypotype. P45575. 



Horizon and locality. Figured specimen, from sample No. 7, Gebel El- 

 Kilabiya section. 



Stratigraphical range. The species was first described from the uppermost 

 Danian (Zone D) of a quarry southwest of Stavnsbjerg farm, Daubjerg (Davbjerg), 

 .Jutland, Denmark, considered by Berggren (1962) as Middle Danian. 



