588 



a nks of sand, and conglomerated galits of por- 

 phyry and lydian fi MM. de Spix and Martius-f* 

 affirm that the banks of the Rio Negro, on the 

 south of the equator, are composed of variegated 

 sandstone ; those of the Rio Branco, Jupura, and 

 Apoporis, of quader sandstone ; and those of the 

 Amazon on several points, of ferruginous sand- 

 stone It remains to examine if, as I am now 

 inclined to think, the limestone and gypsum 

 formations of the eastern part of the Cordillera 

 of the shore of Venezuela, differ entirely from 

 those of the Llanos, and to what soil belongs 

 that rocky wall § which, by the name of Galera, 



* Geogn. Essay, p. £31. 



f (Jeber die Physiognomic des Pfianzenreicks in Brasilien, 

 p. 13, 14. 



J Braunes eisenschussiges Sandstein-Conglomerat (Ironsand 

 of the English geologists, between the jura-limestone and 

 green sandstone.) MM. Spix and Martius found on rocks 

 of quadersunstein, between the Apoporis and k the Japura, 

 the same sculpture which we have made known from the 

 Essequibo to the plains of Cassiquiare, and which seems to 

 prove the migrations of a people more advanced in civiliza- 

 tion than the Indians who now inhabit those countries. 

 (Vol. v, p. 600.) 



§ Vol. iv, p. 279. Is this wall a succession of rocks of 

 dolomie or a dyke of quadersandstone, like mer du Diable, 

 (TeufelsmauerJ at the foot of Harz? Calcareous bands (coral 

 banks) either bands of sandstone (effects of the revulsion 

 of the waves) or volcanic eruptions, are commonly found on 

 the borders of great plains, that is, on the shores of antient 

 inland seas. The Llanos of Venezuela furnish examples of 



