609 



doubt that the gneiss-granite of the Oroonoko 

 is a little auriferous on some points (Vol. iv, 

 p. 471 ; Vol. p. 678, 857 ; Vol. vi, p. 215). 



y. Micaslate forms with clayslate (than- 

 schiefer), a continued soil in the northern chain 

 of the Cordillera of the shore, from the point of 

 Araya, beyond the meridian of Cariaco, as well 

 as in the island of Marguerita. It contains, 

 in the peninsula of Araya, garnets disseminated 

 in the mass, cyanite (Vol. ii, p. 285), and when 

 it passes to clayey-slate, small layers of native 

 alum (Vol. vi, p. 93, 99, 102). Micaslate con- 

 stituting an independant formation, must be 

 distinguished from micaslate subordinate to a 

 soil of gneiss, on the east of Cape Codera. The 

 micaslate subordinate to gneiss, displays in the 

 valley of Tuy, shelves of primitive limestone 

 (Vol. iii, p. 92), and small layers of graphic 

 ampelite (zeicheschiefer) ; between Cape Blanc 

 and Catia, layers of chloritic, granatiferous 

 slate, and slaty amphibol (Vol. iii, p. 404) ; and 

 between Caraccas and Antimano, the more 

 remarkable phenomenon of veins of gneiss in- 

 closing balls of granatiferous diorite* {grun- 

 stein) (Vol. iv, p. 59, 60). 



In the Sierra Parime, micaslate predominates 

 only in the most eastern part, where its lustre 

 has given rise to strange errors (Vol. v, p. 838^ 



* See my geognostic Essay, p. 337. 

 VOL. VI. 2 s 



