380 GRANITE ROCKS. 



tution of the coast and the Sierra Parinie, we prefer to 

 treat of granite, gneiss, and mica-slate, if not as one forma- 

 tion, at least as three co-ordinate formations closely linked 

 together The primitive clay-slate (urthonschiefer) is sub- 

 ordinate to mica-slate, of which it is only a .modification. 

 It no more forms an independent stratum in the New Con- 

 tinent, than in the Pyrenees and the Alps. 



(a) G-R UTTE which does not pass to gneiss is most com- 

 mon in the western part of the coast-chain between Turmero, 

 Valencia, and Porto Cabello, as well as in the circle of the 

 Sierra Parime, near the Encaramada, and at the Peak of 

 Duida. At the Bincon del Diablo, between Mariara and 

 Hacienda de Cura, and at Chuao, it is coarse-grained, and 

 contains fine crystals of felspar, 1 inches long. It is 

 divided in prisms by perpendicular vents, or stratified regu- 

 larly like secondary limestone, at Las Trincheras, the strait 

 of Baraguan in the valley of the Orinoco, and near 

 Guapasoso, on the banks of the Atabapo. The stratified 

 granite of Las Trincheras, giving birth to very hot springs 

 (from 90*5 cent.), appears from the inclination of its layers, 

 to be superposed on gneiss which is seen further southward 

 in the islands of the lake of Valencia; but conjectures of 

 superposition founded only on the hypothesis of an inde- 

 finite prolongation of the strata, are doubtful ; and possibly 

 the granite masses which form a small particular zone in 

 the northern range of the littoral Cordillera, between 70 3' 

 and 70 50' long., were upheaved in piercing the gneiss. 

 The latter rock is prevalent, both in descending from the 

 Eincon del Diablo southward to the hot-springs of Mariara, 

 and towards the banks of the lake of Valencia, and in 

 advancing on the east towards the group of Buenavista, 

 the Silla of Caracas, and Cape Codera. In the region of the 

 littoral chain of Venezuela, where granite seems to con- 

 stitute an independent formation from 15 to 16 leagues in 

 length, I saw no foreign or subordinate layers of gneiss, 

 mica-slate, or primitive limestone.* 



* Primitive limestone, everywhere so common in mica-slate and gneiss, 

 is found in the granite of the Pyrenees, at Port d'Oo, and in the moun- 

 tains of Labourd, 



