608 



slate, while the appearance of a passage to 

 granite is only found on the summit of the 

 Silla de Caraccas * (Vol. iii, p. 508) ; it would 

 still require to be examined with more care 

 than I was able to do, whether the granite of 

 the top of Saint Gothard, and of the Silla of 

 Caraccas, reposes effectively on rnicaslate and 

 gneiss, or if it has merely pierced those rocks 

 rising in the form of needles, or domes. The 

 gneiss of the Cordillera of the shore, in the pro- 

 vince of Caraccas, contains almost exclusively 

 garnets, rutile, titanite and graphite, dissemi- 

 nated in the whole mass of the rock (Vol. iii, 

 p. 417, 418); shelves of granular limestone 

 (ib.) and some metalliferous veins (Vol. iii, p. 

 525, 532 ; Vol. iv, p. 269). I shall not decide 

 whether the grenatiferous serpentine of the 

 table-land of Buena vista be inclosed in gneiss, 

 or whether, superposed upon that rock, it do 

 not rather belong to a formation of weisstein 

 (heptinite) similar to that of Penig and Mitt- 

 weyde in Saxony (Vol. iv, p. 79, 92). 



In that part of the Sierra Parime which M. 

 Bonpland and myself visited, gneiss forms a 

 less marked zone, and oscillates more frequently 

 towards granite than rnicaslate. I found no 

 garnets in the gneiss of Parime. There is no 



* The Silla is a mountain of gneiss like Adam's Peak (in 

 the island of Ceylon), and of nearly the same height. 



