XXVI. Notice of Fossil Shells in the Slate of Tmtagel. 

 By the Rev. J. J. CONYBEARE, 



MEMBER OF THE GEOLOGICAL SOCIETY. 



Read 3d December, 1813. 



J.HE large specimen of slate, bearing the impressions of several 

 shells, which accompanies this note, was procured by Mr. Buckland 

 and myself at the slate quarries of Tintagel, on the north coast of 

 Cornwall. As it has not hitherto been remarked that any traces 

 of organic remains existed in the schistose rocks of that county, 

 we thought that it might not be deemed unworthy of a place in 

 the collection of the Society. 



The quarries which produced it are situated close to the sea, at 

 the distance of about six miles to the north-west of Camelford. 

 They arc worked upon a very large scale, and are celebrated for 

 the excellent quality of the roofing slate which they afford. The 

 nearest point at which granite occurs must be as much as seven 

 miles distant : we were therefore not surprised at the total absence 

 of those large granitic and porphyritic dykes which, whether they 

 are connected with or independent of that primitive rock, are 

 certainly of much more frequent occurrence in its vicinity than 

 elsewhere. The veins produce quartz, rock crystals of great trans- 

 parency and beauty, calcareous spar, chlorite, and in some instances 

 adularia. I know not whether this variety of felspar has been 



