70 Geological Society. 



PliOCEEDINGS OF LEAENED SOCIETIES. 

 GEOLOGICAL SOCIETY. 



February 22, 1893.— W. H. Hudleston, Esq., M.A., F.R.S., 



President, in the Chair. 



The following commnnications were read : — 



1. " On the Microscopic Structure of the Wenlock Limestone, 

 with Remarks on the Formation generally." Bv Edward Wethered, 

 Esq., F.G.S., F.E.M.S. 



Microscopic sections of limestone have been examined from May 

 Hill, Purley, and Ledbury, and the exposures of Wenlock Lime- 

 stone were visited by the Author. As a result of their study, it 

 appears that these limestones have been deposited under varying 

 local conditions. At May Hill, the Wenlock Limestone shows three 

 divisions : — at the base of the qnarry a massive limestone, succeeded 

 by thin-bedded limestones separated by shales, and above these a 

 nodular, irregularly-bedded limestone. The limestone of this district 

 shows abundance of granules similar to Oolitic ones, and it is marked 

 by the occurrence of GirvaneUa lyrohlematica, with new and im- 

 portant forms of the genus GirvaneUa. 



At Purley, near West Malvern, is a section somewhat similar to 

 that at May Hill. Pisolite has been described from this area, and 

 the Author succeeded in finding a weathered block of limestone full 

 of pisolites, whilst sections from the beds at the base of the quarry 

 show them to be more or less oolitic. Amongst other Girvanellce, 

 a form occurs at Purley which has not been noticed at May 

 Hill. 



The Ledbury limestone is very different from those at May Hill 

 and Purley. The variety of calcareous organisms which appear to 

 have contributed to its formation is small. No sign of oolitic struc- 

 ture has been found here, and GirvaneUa is only represented by 

 occasional aggregations of G. jjrohlcmatica., whilst the extraordinary 

 number of forms obtained from May Hill and Parley shows in how 

 great a measure the tubules of this organism have contributed to the 

 formation of the limestones of those places. 



The Author at present offers no opinion as to whether GirvaneUa 

 is animal or vegetable. 



2. " On the Affinities (1) of AntJiracopera, (2) of Anthracomya," 

 By Dr. Wheelton Hind, B.S., F.G.S. 



In this paper the Author gives the generic characters of the 

 genera Anthracojptera and Anthracomya, and discusses their affinities. 

 He gives reasons for supposing that the forms referable to these two 

 genera lived in fresh water. The following species are described : — 



