VEINSTONES. 



trie layers. For these circumstances I shall thus 

 account. The granitic rock being divided into 

 masses by horizontal and vertical fissures, as most 

 granites are, the decomposition arising from the 

 atmosphere would first affect the angles and sides, 

 and reduce them into that kind of gravel of which 

 we have spoken, while the masses of course as- 

 sume the form of balls. The decomposition, 

 afterwards penetrating gradually into their interior, 

 would successively relax the tissue, and thus form 

 concentric layers ; while the inmost part would 

 continue to preserve its solidity, thus forming the 

 kernel. One of the effects of the decomposition 

 has been the oxydation of the iron in the felspar, 

 whence the red colour of the gravel, of the con- 

 centric layers, and all the decayed parts ; while, 

 in the kernel, the felspar is of a very fresh bluish 

 white. This oxydation of iron, by the common 

 influence of the atmosphere, is the cause of several 

 appearances in rocks, particularly the sandstones. 

 In one of the balls, which was on the surface of 

 the earth, the upper hemisphere of layers was en- 

 tirely wanting, the fresh and solid kernel being 

 displayed ; while beneath it was enveloped by the 

 lower hemisphere of decomposed layers, the upper 

 having been carried away by the winds, rains, 

 and other meteoric influences. I report this fact 



