302 THE GEOLOGIST, 



fresli demonstratiou for the sake of geological enquirers, sncli 

 as many of the correspondents of The Geologist mnst neces- 

 sarily be. 



I here propose to offer a note on some of the results of weathering 

 on granite-rocks. My note-book of last year contains one or two 

 sketches illustrating that subject, and reminding me of much that 

 has been written by others about it. 



Lign. 2.— The Cheesewring, near LisMerd, Cornwall. 



In granitic regions we often find the surface of the countries dis- 

 tinguished by peaks and crags ; irregularly prominent masses of 

 rudely-heaped rock-fragments, forming " tors ;" more regularly piled 

 isolated heaps or pillars, such as " cheesewrings ;" and sometimes a 

 peak or pile surmounted by a single, moveable, and well-poised 

 mass, constituting a rocking or logging stone. Figs. 1, 2, and 4, 

 Avhich illustrate these three forms that weathered gTanite-rock pre- 

 sents, are copied from the plates illustrating Dr. M'Culloch's 

 memoir on the granite-tors of Cornwall, in vol. ii. of the Trans- 

 actions of the Geological Society, 1848. In this memoir much 

 valuable information \vi\l be found ; and the difficulties of the sub- 



