[ 278 ] 

 XXXII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 206.] 



December 19, 1888.— W. T. Blanford, LL.D., F.R.S., President, 

 in the Chair. 



^HE following communications were read : — 

 -*- 1. " Trigonocrinus, a new genus of Crinoidea from the ' Weisser 

 Jura ' of Bavaria, with description of new species, T. liratus ; 

 Appendix I. Sudden deviations from normal symmetry in !Neocri- 

 noidea ; and Appendix II. Marsupites testudinarius, Schl., sp." 

 By F. A. Bather, Esq., B.A., E.G.S. 



2. " On ArcJiceoci/atJms, Billings, and on other Genera allied 

 thereto, or associated therewith, from the Cambrian Strata of North 

 America, Spain, Sardinia, and Scotland." By Dr. G. J. Hinde, 

 F.G.S. 



3. " On the Jersey Brick Clay." By Dr. Andrew Dunlop, F.G.S. 

 This clay is of a duU yellow colour and somewhat sandy ; in 



places it effervesces with acids ; bedding and lamination have been 

 noted. The lower part contains angular stones, usually with their 

 longest diameter parallel to the surface of the underlying rock, and 

 either derived from it or from some other rock not far distant. The 

 bulk of the rocks consists of granite, diorite, rhyolite, quartz-felsite, 

 &c., but there is an argillaceous shale, locally hardened, which is 

 largely developed over considerable areas. The clay occurs in patches, 

 covering all kinds of rocks, and is spread over the raised beaches ; 

 it seems more abundant on the higher grounds. A similar clay 

 occurs in Normandy and in the other Channel Islands. 



The author was disposed to regard this clay as probably a fluvia- 

 tile deposit laid down towards the close of the Glacial Period, when 

 the Channel Islands were at a lower level and united to the main- 

 land. Subsequently he conceived that it might be the result of the 

 decomposition of shale, felspathic porphyry, &c., some sections 

 seeming to show this process as still going on ; the clay, too, seems 

 better developed over this class of rock ; if so, it would require a 

 moving force more energetic than ordinary rainwash. 



January 9, 1889.— H. Woodward, LL.D., F.E.S., Vice-President, 

 in the Chair. 



The following communications were read : — 



1. " On the Growth of Crystals in Igneous Eocks after their 

 Consolidation." By Prof. J. W. Judd, F.R.S., F.G.S. 



That the characteristic structures of the " granophyric " rock 

 were not acquired by thera during the act of consolidation, but 

 have resulted from secondary changes taking place subsequently, 

 was suggested in a former communication to the Society. Addi- 



