Geology of Barbados and the West Indies. 287 



ix. The Rubble on the Sides and in the Bed of the Valley. — The 

 author describes this rubble, and rejects the view that it is rain- 

 wash or due to subaerial action, and discusses the possibility of its 

 having been produced by ice-action. 



x. Alluvium and Neolithic Implements. — These occur chiefly 

 between Shoreham and Riverhead. 



xi. On the Chalk Escarpment iviihin the Darent District. — The 

 author, after discussing and dismissing the view v that the escarpment 

 was formed by marine denudation, criticizes the theory that it was 

 due to ordinary subaerial denudation, and lays stress on the irregular 

 distribution and diversity of the drift-beds in the Darent area ; these 

 do not possess the characters which we should expect if they were 

 formed by the material left during the recession of the Chalk escarp- 

 ment owing to subaerial action ; and he believes that glacial agency 

 was the great motor in developing the valleys and, as a consequence, 

 the escarpment, and that the denudation was afterwards further 

 carried on in the same lines by strong river-action and weathering, 

 though supplemented at times by renewed ice-action, fty such 

 agencies, aided by the influence of rainfall and the issue of powerful 

 springs, he considers that the escarpment was gradually pared back 

 and brought into its present prominent relief. 



February 4, 1891.— A. Geikie, Esq., LL.D., F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. " The Geology of Barbados and the West Indies. — Parti. The 

 Coral liocks." By A. J. Jukes-Browne, Esq., F.G.S., and Professor 

 J. B. Harrisor,M.A., F.G.S. 



The authors first discuss the reef growing round Barbados and 

 describe a submarine reef, the origin of which is considered ; and it 

 is pointed out that there is no sign of any subsidence having taken 

 place, but every sign of very recent elevation. They then describe 

 the raised reefs of the island, extending to a height of nearly 1100 

 feet above sea-level in a series of terraces. The thickness of the 

 coral-rock in these is seldom above 200 feet, and the rock does not 

 always consist of coral-debris. At the base of the reefs there is 

 generally a certain thickness of detrital rock in which perfect reef- 

 corals never occur. 



The collections of fossils made by the authors have been 

 examined by Messrs. E. A. Smith and J. W. Gregory. Of the 

 corals, 5 out of 10 species identified still live in the Caribbean Sea, 

 and 1 is closely allied to a known species, whilst the other 4 are 

 only known from Prof. Duncan's descriptions of fossil Antiguan 

 corals. The authors are of opinion that the whole of the terraces 

 of Barbados, the so-called " marl " of Antigua, and the fossiliferous 

 rocks of Barbuda are of Pleistocene age. 



They proceed to notice the formations in other West Indian 



