164 



Rev. 0. Fisher — Glacial Action and Raised Sea-beds. 



I observed there that the minor features of the surface contour are 

 carved out of it and the Millstone-grit alike, which on my theory 

 would make the last general denudation, and therefore the Trail, 

 newer than that clay, and d fortiori newer than the ice-sheet and 

 its till. 



I must admit that I cannot find a statement, as direct as I sup- 

 posed, of my opinion that the overturning of the basset edges has 

 been caused by the passage of ice over them. But I have implied 

 this in a letter to the Magazine, Vol. V., p. 36. Mr. Tiddeman has 

 given a diagram ^ where this phenomenon is connected with ac- 

 knowledged tin, and refers the former to the ice which deposited the 

 latter. I can mention instances where there is no till usually so 

 regarded, and yet this action upon the basset edges is undeniable. 



N. S. 



Reversed laminse of Schorlaceous Granite south of Carclaze Mine, Cornwall. 



One of these I saw last summer in Cornwall, in a cutting on the 

 south side of the famous Carclase mine near St. Austell's. The 

 o-ranite there is greatly disintegrated, and used for china clay. But 

 it is traversed by joints whose walls are schorlaceous and much 

 less decayed. The result is that the entire mass simulates stratifi- 

 cation, which is nearly vertical. It was in this that I observed the 

 reversal of the edges of the laminae, which are bent over towards 

 the south, that is towards the brow of the hill, until they become 

 horizontal. The spot is sufficiently distant from the brow of the 

 till for the declivity of the ground to be very small, but I think the 

 neighbourhood of the brow has something to do with the effect. 

 The disturbed layer is about four feet deep. 



Another instance I noticed in Dorsetshire some years ago. It 

 occurred in a large pit, excavated in Eocene gravel, immediately 

 above the tunnel of the Dorchester and Weymouth railway at Eidg- 

 way Hill. The gi'avel, which is distinctly stratified, and thrown by 

 the great disturbance at that place into a vertical position, has its 

 layers bent over towards the brow of the hill in a manner exactly 

 similar to the case already described as occurring near St. Austell's. 



Another instance may be cited from Torquay, where the edges of 

 the Devonian shale, in a quarry by the roadside, just above the Post 

 office, are turned over in a most marked manner. But here the 

 rocks are on the side of a steep declivity, and the old explanation of 



1 Geol. Journ., vol. xxviii., p. 



481. 



