STUDIES EST FORAMINIFERA 



105 



and Bermudez, and Globorotalia cocoaensis Cushman. 

 There are also numerous upper Eocene benthonic 

 species, e. g., Bulimina jacksonensis Cushman, that do 

 not cross the Eocene-Oligocene boundary. Cassigeri- 

 nella chipolensis (Cushman and Ponton) and the 

 Globigerina ciperoensis Bolli group on the other hand 

 appear for the first tune in the lower Oligocene Globi- 

 gerina ampliapertura zone. 



Apparently normal contacts between the Cipero and 

 Lengua formations have been observed at various 

 localities, such as in trenches in the Barrackpore area. 

 The extinction of Globorotalia fohsi rohusta, the change 

 to a more clayey lithology, and the presence in certain 

 areas of pebble beds and slump-masses of considerable 



thickness are indications not only of environmental 

 changes but also of tectonic and possibly of tm-bidity 

 flow activities at the end of Cipero time. 



The structural complexities in the area of the type 

 section and further to the north (see text-fig. 19) make 

 extremely difficult a satisfactory interpretation of the 

 existing tectonic conditions. The complex pattern as 

 exposed along the Cipero type section is also character- 

 istic for the whole Naparima area fm-ther to the east. 

 With the introduction of the present zonation it has 

 become more and more evident that many of the com- 

 plications in the area are not of a tectonic nature but 

 are probably caused by penecontemporaneous large 

 scale slumping (Kugler, 1953). 



Figure 19. — Type section of the Cipero formation, Trinidad, B. W. I. 



