SLATE FOIIMATIONS. 885 



most violence in the granitic soils of Caracas imd the 

 Orinoco. Igneous phenomena (if their existence be really 

 well certified) are attributed by the people to the granitic 

 peaks of Duida and Guaraco, and also to the calcareous 

 mountain of Cuchivano. 



From these observations, it results that gneiss-granite 

 predominates in the immense group of the mountains of the 

 Parime, as micaslate-gneiss prevails in the Cordillera of the 

 coast; that in the two systems, the granitic soil, unmixed 

 with gneiss and mica-slate, occupies but a very small extent 

 of country ; and that in the coast-chain the formations of 

 clayey slate (thonschiefer), mica-slate, gneiss, and granite, 

 succeed each other in such a manner on the same line from 

 east to west (presenting a very uniform and regular inclina- 

 tion of their strata towards the norlh-west), that, according 

 to the hypothesis of a subterraneous prolongation of the 

 strata, the granite of Las Trincheras and the Bincon del 

 Diablo may be superposed on the gneiss of the Villa de 

 Cura, of Buenavista, and Caracas; and the gneiss super- 

 posed in its turn on the mica-slate and clay-slate of Mani- 

 Suarez and Chuparuparu in the peninsula of Araya. This 

 ypothesis of a prolongation of every rock, in some sort 

 indefinite, founded on the angle of inclination presented by 

 the strata appearing at the surface, is not admissible; and 

 according to similar equally vague reasoning, we should 

 be forced to consider the primitive rocks of the Alps of 

 Switzerland as superposed on the formation of the compact 

 limestone of Achsenberg, and that [transition, or identical 

 with zechstein?] in turn, as being superposed on the molasaus 

 of the tertiary strata. 



II. FOBMATION OF THE CLAY-SLATE (THONSCIIIEFEB) OF 



MALPASSO. If, in the sketch of the formations of Vene- 

 zuela, I bad followed the received division into primitive, 

 intermediary, secondary, and tertiary strata, I might bo 

 doubtful what place the last stratum of mica-slate in the 

 peninsula of Araya should occupy. This stratum, in the 

 ravine (aroyo) of Kobalo, passes insensibly in a carburetted 

 and shining slate, into a real ampelite. The direction and 

 inclination of the stratum remain the same, and the thon- 

 Bchiefer, which takes the look of a transition-rock, is but a 



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