hill: geology of Jamaica. 131 



the same valley as Catadupa aud Cambridge. This is the only Cepha- 

 lopod as yet found in Jamaica, and is probably the same form which has 

 been referred to as Aturia zigzag. If its position and determination 

 could be verified, it would prove another valuable testimonial to the 

 Eocene age of the beds, as this form is characteristic of the late Eocene 

 of the United States. De la Beche ^ has noted the occurrence of a 

 Nautilus, probably the same as that previously mentioned from Cuba, 

 a Terrebratula, and Nummulinse in association with other species near 

 Halse Hall House, Clarendon. No other specimens of fossil Cephalo- 

 poda have been found in Jamaica. 



Of the fossil Mammalia, only a single fossil trace has been discovered 

 in Jamaica, Prorastomus sirenoides Owen,^ a species of Sirenia related 

 to the Manatees of to-day. This specimen was reported from Freeman's 

 Hall Estate in the southeastern corner of Trelawney near the centre of 

 the island. The locality from which this specimen came is a typical 

 outcrop of the Cambridge beds as described by Brown,^ and Owen's 

 description of the material in which the specimen was embedded con- 

 forms also to the lithologic character of that formation. While no final 

 opinion can be expressed without seeing the specimen and locality, 

 the evidence certainly points to the early Eocene age of this animal.* 

 Being a marine animal, its occurrence in the rocks of Jamaica is of 

 no significance in tracing previous relationships of Jamaica to other 

 islands. 



This fauna of the Cambridge formation is remarkable in several ways. 

 First, for the peculiar mixture it affords at Catadupa of Eocene and 

 Cretaceous genera; and secondly, from its collective dissimilarity to 

 any other known fauna, especially to those of the American continental 

 littoral formations. When a small collection from Cambridge was 

 collected by us in 1896 and submitted to a Tertiary paleontologist of 

 note, it was rejected by him on the ground that it was not of Tertiary 

 age, but Cretaceous, and this too before true Rudistes had been recog- 

 nized in it. Recognizing its absolute dissimilarity to any known Ameri- 

 can Cretaceous fauna, we revisited the region in 1897, and discovered 



1 Nautilus Cubensis, Lea. Trans. Am. Pliil. Soc, 1841, Vol. VII.^. 259. 



2 Quart. Jour. Geol. Soc, 1855, Vol. XL pp. 541, 543. 



3 Jamaican Reports, p. 224. 



^ Marine deposits of the Cretaceous and early Eocene periods are recognized all 

 over the world, but not a trace of tlie Cetacea and Sirenia have been found in 

 them. So far as known, these types appear fully evolved at the top of the Eocene. 

 — Nat. Science, October, 1897, page 223. 



