proceedings: geological society 189 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



The 302d meeting was held in the lecture room of the Cosmos Club 

 on January 12, 1916. 



INFORMAL COMMUNICATIONS 



Max W. Ball exhibited photographs of the results of an earthquake 

 which occurred about 50 miles south of Winnemucca, Nevada. The 

 pictures were taken by S. L. Gillan, Mineral Inspector, General Land 

 Office. 



REGULAR PROGRAM 



T. Wayland Vaughan: Some littoral and sub-littoral physiographic 

 features of the Virgin and Leeward Islands. A discussion of submarine 

 terraces, their significance, the criteria for determining their relative age, 

 and their relation to the development of coral reefs. Illustrated. 

 (Published in full in Journ. Wash. Acad. Sci. 6: 53-66. 1916.) 



0. E. Meinzer: Physical features of Guantanamo Bay and adjacent 

 areas in Cuba. The rocks in the region comprise: (1) a basal complex 

 of metam orphic and igneous rocks; (2) a sedimentary series, several 

 thousand feet thick, consisting chiefly of conglomerate, limestone, and 

 shale resting unconformably on the basal complex and in general 

 dipping away from its outcrops; (3) horizontal beds of conglomerate 

 and coralline limestone underlying a series of terraces and resting 

 unconformably on the basal complex and on the tilted beds of conglo- 

 merate, limestone, and shale; (4) stream gravels; and (5) recent marine 

 and delta deposits. Fossils collected in 20 localities have not yet 

 reached Washington. Four marine terraces are well developed — 

 in most of the region at altitudes of about 40, 200, 500, and 750 feet. 

 They consist largely of benches cut into the older rocks (Series 1 and 2) 

 and mantled with coralline limestone (Series 3). Their development 

 in the interior valleys indicates that the present major topographic 

 features were in existence prior to the terraces. They rank in age 

 according to their altitudes. All bear evidences of geologic youth 

 and were apparently formed in the Quaternary period. After the 40- 

 foot terrace was formed the region stood higher than at present, as is 

 indicated by innumerable small bays and estuaries which were created 

 through the dissection of the 40-foot terrace limestone, and by a sub- 

 merged bench (or series of benches) 100 feet or less below present sea 

 level. That the shore line has for a long time been stationary is shown 

 by the existence of a well-developed bench at present sea level. 



G. S. Rogers: Oil field waters and their chemical relations to oil; 

 particularly the conversion of sulphates into carbonates by hydrocarbons. 

 It has long been known that oil and gas are commonly associated with 

 water, but of the chemical relations between the two we know little, 

 and scientific literature contains only a few references to the chemical 

 composition of the waters themselves. The study of several hundred 

 analyses of water from the oil fields of the San Joaquin Valley, Cali- 



