hill: geology of Jamaica. 137 



that " the fuuna of the West Indian seas in those remote times appears 

 to have been as remote from that of the shores of the United States as 

 it has lately been shown by Mr. Bland to be at the present day." ^ 



Fossils of the Montpelier White Limestone. 



As a rule, the Tertiary White Limestones which succeed the Cambridge 

 beds^ although almost entirely of organic origin, are singularly free from 

 macroscopic fossils, especially the lower half of the Series. There is 

 a current impression that the white limestones, as a whole, are richly 

 fossiliferous, owing to the fact that many shells from the Bowden horizon 

 have been described as coming from the " White Limestones of Jamaica," 

 but, as we have shown, the Bowden beds are not White Limestones, but 

 gravels and argillaceous marls. De la Beche notes many shells from the 

 White Limestones, but all came either from the underlying Cambridge 

 beds or the overlying Post-Tertiary White Limestones of the Coastal 

 Series which we have separated from the true Tertiary White Lime- 

 stones. 



Minute search for such fossils in hundreds of exposures has generally 

 been without success. Except the beds at Port Antonio, which are of 

 Cambridge affinities, the Moneague beds and a few places in the Bog 

 Walk section, the great mass of the White Limestones are barren of such 

 remains so far as we have observed them. This noteworthy absence 

 may in some instances be due to secondary alteration of the rocks, but, 

 in general, it is owing to the fact that the material originated at depths 

 beyond that in which the abundant littoral molluscan life occurred. 

 Notwithstanding the absence of macroscopic remains, the Montpelier 

 beds, which compose the lower 500 feet of the White Limestones, are 

 almost entirely made up of foraminiferal remains, — Orbitoides, Num- 

 mulinse, and Miliolidse at the base, grading up into Globigerinal deposits. 

 These beds are very free from remains of shallow water corals, — a fact 

 which further supports the theory that they were deposited at great 

 depths beyond that at which these organisms could flourish. The great 

 subsidence of this epoch undoubtedly must have extinguished most of 

 the dense molluscan life, which does not appear again until the Bowden 

 epoch. 



Radiolaria are rare in the Jamaican rocks, our specimens from the 

 Montpelier beds usually showing only a few traces of them, — certainly 



1 T. C. Moore, Quart. Jour. Geol. Soc. London, Vol. IX. p. 131. 



