216 bulletin: museum of comparative zoology. 



stone and marls of shallow water origin. The limestones may be of the 

 type of the Pliocene Manchioneal formation of eastern Jamaica, which is 

 sparse in identifiable molluscan remains, although containing Pteropods 

 and Brachiopods and a few thin beds of modern reef corals ; or of the 

 Falmouth type, largely composed of shells, in which the remains of a 

 certain species of Bulla are specially abundant. I know of the occur- 

 rence of all these formations in stratigraphic juxtaposition only in Jamaica, 

 although types of each have wide distribution throughout the Tropical 

 region at altitudes nowhere exceeding 250 feet excepting in Barbados and 

 the inner margin of the Caribbee Islands. 



The oldest and highest group of these levels, composed of no later 

 strata than the old Oligocene, may probably have been developed on 

 the emerging land between the Montpelier and Bowden epochs of subsi- 

 dence. They may present old levels engraved upon the margins of this 

 Antillean land during the erosive epochs accompanying and following 

 the culminating orogenic uplift. This is the level preserved on the 

 summits of the Pan de Matanzas and Yunki of the north coast of Cuba, 

 and the 2,000 foot limestone benches against the Sierra Maestra of the 

 south side of the same island j also the John Crow and Yallahs Moun- 

 tain levels of Jamaica. 



The middle group may be of late Pliocene and early Pleistocene age, 

 while the newer or coastal group, characterized by being largely composed 

 of elevated reef rock, is the product of the late Pleistocene or recent 

 emergence. 



After the Bowden subsidence, there was further elevation, which added 

 the Bowden formation to the Antillean margins. This was not so in- 

 tense in amplitude as the preceding orogenic uplift, but far reaching in 

 its effect and geographic importance. The Antilles were expanded to 

 areas probably embraced by the present 100 fathom lines, enlarging 

 the eastern and southern margins by narrow ribbons of restored land. 

 This uplift was greatest on the continental mainland, the movement 

 being less felt in the Antilles. 



The whole of the Coastal Plain, with its Appalachian background and 

 the Great Plains region of the United States, and probably the Cordilieran 

 region also, participated in this upward movement. Southern Florida, 

 heretofore West Indian in its relations, was united with the land to the 

 north and became populated with North American mammals. The 

 island could have had no Antillean or Bahaman connection at this time, 

 for these mammals are not found in the latter regions. The elevation, 

 however, was not sufl&cient to establish a united Antillean continent 



