PROCEEDINGS 
OF THE 
GEOLOGICAL & POLYTECHNIC SOCIETY 
AT THE FORTY-SECOND MEETING, HELD IN THE CUTLERS’-HALL, 
SHEFFIELD, ON THURSDAY, JUNE 5tH, 1851. 
Alderman Thomas Dunn having taken the Chair, the 
following gentlemen were elected Members of the Society: — 
W. H. Jeffcock, Esq., Sheffield. 
H. C. SoRBY, Esq., Sheffield. 
Thomas Wilson, Jun., Esq., Sheffield. 
John Jebson, Esq., Huddersfield. 
The Chairman, after addressing the Society in a short 
speech, called upon Mr. Sorby to read the first paper: — 
ON THE MICROSCOPICAL STRUCTURE OF THE CALCAREOUS 
GRIT OF THE YORKSHIRE COAST. BY HENRY CLIFTON 
SORBY, ESQ., F.G.S. 
The calcareous grit is a sandstone containing a variable 
quantity of carbonate of lime, which lies just below the 
coralline oolite. Good sections of it may he seen at Filey, 
Gristhorpe Bay, and Scarborough. A great part of it is 
only a sandstone containing a variable quantity of calcareous 
matter, hut a considerable portion contains a great deal, 
and is much hardened by the infiltration of agate, which has 
silicified many of the shells and the wood, and filled the 
chambers of many of the ammonites. It is to this part of 
the bed that I wish to call attention. 
If a piece of it be dissolved in hydrochloric acid, we obtain 
portions of agatized shells, and a quantity of sandy matter, 
VOL. III. 
o 
