220 ME. JITKES-BROWIJE AlfD PEOF. HAEETSON 



is labelled ' Post-Pliocene.' Mi\ Barrington Brown, however, tp 

 whom we wrote on the subject, informs us that this last reterejice 

 was a mistake ; that during the course of the Survey and before the 

 fossils were examined there was naturally much uncertainty with 

 respect to its age, but it was finally intended to class it as Pliocene, 

 because it was found to rest on a fossiliferous yellow limestone 

 which was considered by Mr. E. Etheridge to be of Miocene age, and 

 probably late Miocene. 



An observation of Prof. Gabb's ^ has an indirect bearing on this 

 point : after stating that the Miocene strata of San Domingo have 

 yielded over 300 species of fossils, including nearly all that have 

 been found in Jamaica, thereby establishing the identity of the 

 formation in the two islands, he says " the present collections have 

 so materially changed the correlation between the fossil and living 

 faunae that it is necessary to do the greater part of the work over 

 again." He finds there are 217 extinct and 97 living species, the 

 proportion of living forms being bet Aveen 30 and 33 percent., which 

 is higher than Lyell's estimate of the proj^ortion in the Miocene of 

 the Loire. He was therefore inclined to regard the beds as Pliocene, 

 but the presence of several antique types prevented him from taking 

 this step ; and he agrees with Mr. E. Etheridge in placing the Jamaica 

 and San Domingo beds, together with the Caroni formation of 

 Trinidad, in the upper or later division of the Miocene. 



This is doubtless the true place of the Jamaica yellow limestone, 

 for Lyell's estimate is now known to be too low, and recent re- 

 searches make it probable that the proportion of living species in the 

 Eaiuns of the Loire is from 30 to 40 per cent. This being so, it is 

 clear that the overlying White Limestone Series cannot be older than 

 early Pliocene. 



Besides the White Limestone there are in Jamaica deposits of 

 raised pteropod ooze which are thus described by Mr. Lucas Barrett 

 (' Geology of Jamaica,' p. 82) : — " A remarkable fossiliferous marl 

 occurs on the south coast of St. Thomas-in-the-East, on the east 

 coast by Manchioneal, and on the north coast of Portland near Port 

 Antonio, often forming elevations 300 feet high. It is characterized 

 by a peculiar assemblage of organic remains, consisting of pteropoda, 

 a few bivalve and univalve moUusca, with some gigantic foraminifera. 

 It is evident that the deposition of this marl took place at a con- 

 siderable depth . . . this is confirmed by the result of some dredging I 

 had on the north coast, where from the depth of 150 to 200 fathoms 

 the dredge brought up the whole of the mollusca and foraminifera I 

 had before collected from this marl. This shows that since the 

 deposition of this stratum, which is of Pliocene age (for deep-water 

 mollusca have a greater range in time than shallow-water species), 

 the coast has been elevated at least ] 200 feet ... It was this elevation 

 that impressed the physical features, the coast-lines, littoral moun- 

 tain-ridges, and parallel fissures on the east coast of Jamaica, 

 modifying the efiect of previous disturbances and illustrated by 



1 Trans. Amer. Phil. Soc. 1881, n.s. vol. xv. p. 99. 



