﻿THE 



QUARTERLY JOURNAL 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY. 



November 6, 1850. 



The following communications were read : — 



1. On the Microscopical Structure of the Calcareous Grit 

 of the Yorkshire Coast. By Henry Clifton Sorby, F.G.S. 



If a piece of that part of the calcareous grit just below the coralline 

 oolite, which contains numerous agatized shells, be dissolved in hy- 

 drochloric acid, we obtain portions of agatized shells, and a quantity 

 of sandy matter, which without further examination would naturally 

 be thought to be merely sand, and such it has hitherto been con- 

 sidered. When however examined with a microscope, it is at once 

 seen to contain a very large quantity of reniform bodies, which are 

 evidently not sand, but some kind of minute organisms converted 

 into agate. The mere occurrence of minute agatized shells in this 

 deposit would certainly not be a fact worthy of being laid before this 

 Society, but since they exist in such vast numbers as to constitute a 

 very considerable portion of a well-known rock, and by the manner 

 in which they occur are presented to us in a form that is additionally 

 interesting, perhaps a detailed account of them will not be thought a 

 subject unworthy of attention. 



The chemical composition of a specimen containing no large shells 

 was determined by dissolving it in hydrochloric acid ; and the fine 



VOL. VII. PART I. B 



