NOME XIX. GRANITE AND SLATE. 



confirms the same truth that granite may be 

 formed in the water, by the simultaneous crys- 

 tallisation of two or three kinds of stone. The 

 granite rock, on which this town is built, na- 

 turally divides itself into large masses, with 

 plane or flat sides, and these masses are here and 

 there separated by crevices of a certain breadth. 

 I found in these crevices parcels of quartz, fel- 

 spar, and mica, mingled as in granite, but in 

 far larger grains, there being bits of an almost 

 transparent quartz, two or three inches thick, 

 traversed by leaves of mica so large that they 

 might be called talc, or Muscovy glass; and 

 the whole intermingled with large pieces of red 

 felspar, like that of the granite, and confusedly 

 crystallised. It could not be doubted, on seeing 

 these heaps of large crystals, that they are the 

 produce of the rain waters, which, passing 

 through the granite, have dissolved and carried 

 down these different elements, and have depo- 

 sited them in these wide crevices, where they 

 are crystallised, and have formed new stones of 

 the same kind. The crystals of these new gra- 

 nites are larger than those of the ancient, on 

 account of the repose which the waters enjoyed 

 in the inside of these reservoirs." 



Such are the remarks of this great observer, 

 who proceeds to argue that granite was ori- 



