144 Dr. Berger o;z the physical Structure 



an individual fact, and one of so little extent, were It not that It 

 offers an exception to what I consider as a general law in Cornwall, 

 I tnean, the direction and inclination of the grauwacke strata. 



A semi-circular beach, covered with fine sand, in front of which 

 stands, in a magnificent bay, St. Michael's Mount, topped by its 

 gothic castle, affords a delightful walk the whole way from Marazion 

 to Penzance. The land rising on both sides, breaks the uniform 

 though imposing grandeur of a horizon bounded by the vault of 

 heaven, and the picture taken in its whole extent, forms one of 

 the most beautiful landscapes that the human eye can contemplate. 



At the entrance of Penzance, I remarked some rocks of common 

 grauwacke, which were not I believe in situ. We find in the neigh- 

 bourhood, indications of this rock, but only close by the sea, shew- 

 ing, that its geological situation is the same throughout the whole 

 extent of Cornwall. Thus, on leaving the village of Newlyn, on 

 the road from St. Paul, it is seen distinctly ;';/ situ^ but one hundred 

 and fifty paces farther, the land rising, though but a little, the grau- 

 wacke is lost, and we enter upon the granite. From St. Paul to 

 Mouse-hole, by the sea side, the land again falls, and we re-enter 

 the grauwacke about two or three hundred paces from the church- 

 yard of St. Paul. It is remarkable that the grauwacke, although in 

 so low a situation, is no longer slaty, but compact ; it is here, how- 

 ever, near the point of its junction with the granite, a circumstance 

 which, more than its absolute height above the level of the sea, de- 

 termines its particular structure. At the south end of the village of 

 Mouse-hole, the granite lowers so much, that the grauwacke can 

 only be seen at low water. It contains much quartz, and even 

 felspar, and at the place of junction, there are several veins of granite 

 seen shooting through it. 



