1863.] DUNCAN WEST INDIAN COKALS. 455 



Miocene period of Europe by the production of a great change of 

 climate and the consequent introduction, by emigration, of forms 

 with more or less arctic affinities into the European fauna and flora — 

 if this be held to be a reasonable explanation of the cause of the 

 difference between the Miocene and Pliocene formations in Europe, 

 corresponding data exist to connect the end of the Miocene Coral- 

 fauna of the West Indies with the physical revolution which closed 

 the Pacific from the Caribbean. 



The peculiar Coral-fauna of the Caribbean Sea is strongly repre- 

 sented in all the superficial deposits of the Islands, and there are no 

 forms, so far as is yet known, amongst these which have other than 

 West Indian affinities. Some genera are found which prove that 

 the causes producing the more or less arctic condition of the European 

 Pliocene, affected very slightly the climate of the Caribbean Sea also. 

 But in all the calcareous formations which are coralliferous and are 

 considerably elevated above the level of the Caribbean Sea, there 

 is a very limited series of Corals with generic relation to those now 

 existing and characteristic of the West Indian Coral-fauna, but a 

 predominance of forms resembling those of the present Coral-seas of 

 the Pacific, South Sea, and the Indian Ocean*. 



The most strongly marked West Indian species are not represented, 

 even in the raised beds, by allied species; and it can readily be 

 believed that a great change in the distribution of land and sea 

 preceded the extinction of the Corals with Pacific affinities. 



In the Coral-seas of the South Sea, Pacific and Indian Oceans, 

 and Red Sea, the external circumstances which are so well known 

 to influence Coral-life are very different from those which operate 

 in the restricted West Indian regions. 



In the first there is an extraordinary freedom from the effects of 

 great rivers, such as pour mud and fresh water for leagues into the 

 pent-up Caribbean Sea : in the great Ocean there are opportunities for 

 migration of species, but in the case of the Caribbean there are impedi- 

 ments on all sides : in the Coral-islands of the Pacific the soundings 

 are soon found to be great ; but in the northern part of the Carib- 

 bean, the great banks, which in their shallow sea somewhat resemble 

 the shoals to the north of the Malay Archipelago, are rarely affected 

 by the furious surf and force of wave, which appear to determine 

 the persistence of several species ; on the contrary, peculiar genera 

 are seen to flourish around Cuba and the Bahamas. 



The presence of species of Alveopora, Stylophora, Flabellum, 

 Placotroclius, Rhodarcea, Astroria, Coeloria, &c, in the raised Coral- 

 formations must refer to a different condition of the physical circum- 

 stances of the West Indian seas from that now existing, and to those 

 peculiarities of climate, of sea-depth, purity and force of sea, and of 

 coast-line, which are noticed in the ocean between Eastern Africa 

 and America. It is worthy of notice that, at the present time, the 

 Australian, Pacific, and Indian Ocean Corals differ as a rule in 

 species and often in genera, that the nearest coral-reef is hundreds 



* Mr. J. Carrick Moore asserts that the San-Domingan Shells have a Pacific 

 facies ; see Quart. Journ. Geol. Soc. vol. vi. 1850, p. 43, and vol. ix. 1853, p. 131, 



