581 



If, in the granitic soil which is here a very 

 complex formation, we would distinguish mine- 

 ralogically between the rocks of granite, gneiss, 

 and micaslate, we must recollect that accord- 

 ing to my local observations, the granite with 

 large grains, not passing to gneiss, is very rare 

 in this country. It belongs peculiarly to the 

 mountains that bound the basin of the lake of 

 Valencia towards the north ; for in the islands 

 of that lake, in the mountains near the town of 

 Cura, and in the whole northern chain, between 

 the meridian of Victoria and Cape Codera, gneiss 

 predominates, sometimes alternating (Silla de 

 Caraccas) with granite, or passing (between 

 Guigue and Villa de Cura, mountain of Cha- 

 coa) to micaslate *. The micaslate is the most 

 frequent rock in the peninsula of Araya *f- and 

 the groupe of Macanao which forms the western 

 part of the island of Marguerita. On the west 

 of Maniquarez, the micaslate of the peninsula 

 of Araya loses by degrees (Cerro de Chuparu- 

 paru) its half-metallic lustre ; it is charged with 

 carbon and becomes a clayslate (thonschiefer) ^, 

 even an ampelite (alaunschiefer). The beds of 

 granular limestone are most common in the 

 primitive northern chain, and, which is some- 



* Vol. iv, p. 273, &c. 

 + Vol. ii, p. 291. 

 t Vol. vi, p. 101. 



