UPPER CRETACEOUS FORAMINIFERA FROM TRINIDAD 



By Joseph A. Cushman and P. W. Jarvis 



Cushman Laboratory for Foramini feral Research, Sharon, Mass. 



INTRODUCTION 



Cretaceous foraminifera have already been described from Trini- 

 dad/ but further collecting and continued study of Trinidad mate- 

 rial have increased considerably the fauna already described in this 

 previous paper. Though the arenaceous forms are often badly dis- 

 torted, on account of pressure and conditions of fossilization, the 

 calcareous forms are usually well preserved and show much of 

 their original detail. The entire collection represents a rather deep- 

 water fauna that is not common in the Upper Cretaceous deposits 

 of the general Gulf Coastal Plain of the United States, although the 

 Velasco shale of the Tampico region represents most nearly the con- 

 ditions under which these Cretaceous deposits of Trinidad were laid 

 down. The Trinidad material, however, is very much better pre- 

 served than that of most of the Velasco shale, and it is therefore 

 much better for detailed studies. 



Many of the genera and also many of the species of the arenaceous 

 group that are still living in the deeper waters off the coast of Trini- 

 dad are to be found in this Cretaceous material, often in considerable 

 numbers. Such genera as Gloinospira, ATumodiscus, Ammodiscoides, 

 Affimolaffena, HorTnosina, jSaccorhisa, and others are common in the 

 Trinidad collections. All these genera are known living off Trini- 

 dad and usually in the same species, so that they seem to indicate 

 that conditions of deposition for this material in the Upper Creta- 

 ceous are not very different from those that obtain off these coasts at 

 the present day. 



As already known from studies of the general Upper Cretaceous 

 of the Gulf Coastal Plain of the United States, most of the species 

 found are already described by various European workers from 



1 Cushman and Jarvis, Cretaceous foraminifera from Trinidad. Contr. Cushman Lab. 

 Foram. Res., vol. 4, pp. 85-103, pis. 12-14, December, 1928. 



No. 2914.— Proceedings U. S. National Museum, Vol. 80, Art. 14. 



70827—32 1 1 



