Geological Society of London. 139 



IL— February 4, 1891.— A. Geikie, LL.D., F.R.S., President, in 

 the Chair. — Tlie following; communications were read : — 



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

 The Coral Rocks." By A. J. Jukes-Browne, Esq., F.G.S., and 

 Professor J. B. Harrison, 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 thick- 

 ness of the coral-rock in these is seldom above 200 feet, and the 

 rock does not always consist of coi'al-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, five 

 out of ten species identified still live in the Caribbean Sea, and one 

 is closely allied to a known species, whilst the other four are only 

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

 The authors are of opinion that the wh(de 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 

 islands which appear to be raised reefs comparable with those of 

 Barbados, and show that these reefs occur through the whole length 

 of the Antillean Chain, and indicate a recent elevation of at least 

 1300 feet, and in all probability of nearly 2000 feet. It appears 

 improbable that each island was a region of separate uplift, and as 

 a plateau of recent marine limestone also occurs in Yucatan, this 

 carries the region of elevation into Central America, and it is 

 reported that there are raised reefs in Colombia. The authors 

 conclude that there has been contemporaneous elevation of the 

 whole Andean Chain from Cape Horn to Tehuantepec and of the 

 Antillean Chain from Cuba to Barbados. Before this there must 

 have been free communication between the Atlantic and Pacific 

 Oceans, which is confirmed by the large number of Pacific forms 

 in the Caribbean Sea. Under such geographical conditions the 

 great equatorial current would pass into the Pacific, and there would 

 be no Gulf Stream in the North Atlantic. 



2. " The Shap Granite, and the Associated Igneous and INIeta- 

 morphic Rocks." By Alfred Harker, Esq., M.A., F.G.S., and J. E. 

 Marr, Esq., M.A., Sec. G.S. 



The authors describe the normal granite of the intrusion, and 

 discuss the characters of certain variations from the usual type. 



The dykes and sills of the neighbourhood are also considered ; 

 the similarity of some of these to certain inclusions in the granite 

 is noticed ; and reasons are given for supposing that many of the 

 felsites and mica-traps of this region are connected with a magma 

 which was intruded amongst the Lower Palgeozoic rocks in pre- 



