564 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 25, 



faunas, viz. the Cretaceous, the Eocene, the Lower Oligocene, the 

 Miocene, and the existing Coral-fauna ; and, 2nd, that the duration 

 of the reefs was vast ; for in Europe the Eocene reefs are very thick, 

 and are separated hy a deep flysch from the great coralliferous Oli- 

 gocene deposits. 



The longer a reef lasts the less probable is the preservation of its 

 earliest components, and age after age produces slight but, in the long 

 run, important variations in the general composition and nature of the 

 fauna ; so that it is impossible to obtain the forms which link a reef 

 to its predecessor. Only the latest forms are preserved, or those which 

 were flourishing when the changes commenced which determined the 

 destruction of the reef. The ordinary wear and tear, the very nature 

 of the superpositing reef-builders, and the metamorphosis of coral 

 limestone are opposed to the perpetuation of very old specimens. 



Hence, when the Eocene deposits of St. Bartholomew's are ex- 

 amined, only the last page of the history is read ; and were it not for 

 the persistence of some types, the nature of their early times would 

 be a closed book. 



They included at the last a species (Astroccenia ramosa) and varieties 

 which are eminently characteristic of the Gosau area ; and as the 

 Hippurite-chalk of Jamaica has been proved to contain similar species 

 to those which then flourished in the Gosau chalk, so it is reasonable 

 to infer tbat these lingering forms were the descendants of the Coral- 

 fauna which preceded the Eocene in the Caribbean area. 



I believe that the other species of Astroccenia are the result of the 

 modification in their secondary characters of the above-mentioned 

 Astroccenia ramosa — a very variable form. Now the St. -Bartholomew 

 Stephanocosnice belong to a Cretaceous group with eight septa; and 

 the costse of the TrocJiosmilice are eminently suggestive of some forms 

 described by Beuss from Gosau. 



The genera Leptoria, Oortiastrcea, and Actinacis were well repre- 

 sented in the European " Craie tuffeau ; " and as there was a commu- 

 nity of species at the time of the deposition of its sediments and those 

 of the Cretaceous of the Northern Caribbean, it is reasonable to assert 

 that the Eocene species were the modified descendants of those which 

 flourished in the preceding cretaceous reefs. 



The St.-Bartholomew deposits contain species which in Europe 

 belong to two Lower Tertiary horizons, the Nummulitic and the 

 Lower Oligocene ; and it would appear that a great subsidence de- 

 termined in Europe the formation of the Elysch which is intercalated 

 between the two deposits. No such sediment is found in the West 

 Indies ; and it is therefore highly probable that the Oligocene reefs 

 of the Castel-Gomberto districtwere supplied with certain species which 

 could last there from the West-Indian and Atlantic reefs. This 

 change of habitat naturally produced variation ; and the magnificent 

 Coral-fauna of the Vicentin and its neighbourhood resulted. 



It is an interesting fact that Cretaceous, Eocene, Miocene, Plio- 

 cene, and recent reefs should have followed each other in the same 

 area, and that volcanic action should have been more or less intense 

 there during these long periods. 



