277 



The zone of gneiss, which we have just men- 

 tioned, is, in the chain of the coast/ from the 

 sea to the Villa de Cura, ten leagues broad. 

 In this great extent of land, gneiss and mica- 

 slate are found exclusively, and these constitute 

 one formation # . Beyond the town of Villa de 

 Cura and the Cerro de Chacao, the aspect of 

 the country becomes more varied to the eye of 

 the geognost. There are still eight leagues 

 of declivity from the table-land of Cura, to the 

 entry of the Llanos ; and, on the southern 

 slope of the mountains of the coast, four dif- 



* A formation which we shall call gneiss-micaslate, and which 

 is peculiar to the chain of the coast of Caractas. Five formations 

 must he distinguished, as Messrs. von Buch and Jtaumer 

 have so ably demonstrated in their excellent papers on 

 JLandeck and the Riesengebirge, namely (a) granite} (b) 

 grariite-gneiss ; (c) gneiss ; (d) gneiss-micaslate ; (e) mica-slate. 

 The geognosts, whose researches have been confined to a 

 small tract of land, having confounded these formations, 

 which nature has separated in several countries in the most 

 distinct manner, have admitted, that the gneiss and mica- 

 slate alternate every where in superimposed beds, or furnish 

 insensible transitions from one rock to the other. These 

 transitions and alternating superpositions take place no doubt 

 in formations of granite- gneiss, and gneiss-micaslate; but 

 because these phenomena are observed in one region, it does 

 not follow, that in other regions we do not find very distinct, 

 circumscribed formations of granite, gneiss, and mica-slate. 

 The same considerations may be applied to the formations of 

 serpentine $ which are sometimes isolated, and sometimes 

 belong to the eurite, mica-slate, and gruenstein,. 



