Physical Geology of the West Indies. 151 



February 20th. — Dr. Henry Woodward, F.P.S., President, 



in the Chair. 



The following communications were read : — 



1. ' Contributions to the Palaeontology and Physical Geology of 

 the West Indies.' By J. W. Gregory, D.Sc, F.G.S. 



The earlier part of the paper is largely concerned with the corals 

 of the raised reefs of Barbados, and, on account of the confusion in 

 the synonymy of the West Indian corals, the synonymy of the 

 species is given in some detail. A list of the mollusca of the Low- 

 level reefs follows. 



The occurrence of the ' Oceanic Series ' of beds over wider areas 

 than generally recognized is proved by the existence of Radiolarian 

 Marls in Cuba, as announced in the discussion on Messrs. Jukes- 

 Browne and Harrison's paper (Q. J. G. S. vol. xlviii. 1892). Tho 

 author gives a list of species of Padiolaria from the Cuban deposit, 

 all of which are also found in that of Barbados. Additions to the 

 fossil fauna of Antigua are recorded. 



In discussing the age of the Barbados rocks, the author states 

 that there is now no doubt that the following is the sequence (in 

 descending order) : — 



x> • i n i -d t \ Low Level : Pleistocene. 

 Kaised Coral Beefs. | ffigh Leyel . pHocene 



{Archceopneustes-abruptus- ( Miocene (and possibly partly 

 limestone. -1 Pliocene) and partly Oli- 



Thalassic Marls. [ gocene. 



Scotland Beds Oligocene (probably Lower). 



The fauna of the Low-level Reefs proves their late Pleistocene age. 

 Until more mollusca are collected from the High-level Reefs, it will 

 not be possible to decide whether the whole are Pleistocene, or 

 whether some must be included in the Pliocene ; it is probable that 

 the latter will have to be done. The Scotland Beds are referred to 

 the Oligocene. This narrows the limit for the time of formation of 

 the deep-sea oozes. Further light is thrown on this question by 

 examining the evidence for the period of submergence of the Panama 

 Isthmus, from consideration of the resemblances of the marine 

 faunas on either side, and the earliest migrations of terrestrial 

 animals across the Isthmus since its elevation. The author puts 

 the period of final emergence of the peninsula in Miocene, or possibly 

 late Oligocene, times, and maintains that there is no evidence of 

 the connexion of Atlantic and Pacific in this region since then. 



He gives reasons for supposing that a subsidence of the Caribbean 

 Sea was simultaneous with this emergence of the Isthmus, and that 

 this subsidence plunged part of the area now occupied by land into 

 abysmal depths in which were deposited the deep-sea oozes of 

 Barbados, Trinidad, and Cuba. In some part of the Miocene or 

 Pliocene re-elevation began, and shallower-water deposits (the 

 Archceopneustes-limestone) were laid down. Elevation continued, 



