384 



them with the hand. In the valleys of Aragua, 

 where they are very common, we have seen them 

 perch upon our hammocks, while we were re- 

 posing" in them in open day. 



We discover between Calabozo, Uritucu, and 

 the Mesa de Pavones, wherever men have made 

 excavations of some feet deep, the geological 

 constitution of the Llanos. A formation of red 

 sandstone* (or ancient conglomerate) covers 

 an extent of several thousand square leagues. 

 We shall find it again hereafter in the vast plains 

 of the Amazon, on the eastern boundary of the 

 province of Ja'en de Bracamoros. This prodi- 

 gious extension of red sandstone, in the low 

 grounds that stretch along the East of the 

 Andes, is one of the most striking phenomena, 

 with which the study of rocks in the equinoctial 

 regions furnished me. 



The red sandstone of the Llanos of Caraccas 

 lies in a concave position *f~, between the primi- 

 tive mountains of the shore and of Parime. On 

 the North it is backed by the transition slates %, 

 and on the South it rests immediately on the 

 granites of the Oroonoko. We observed in it 

 rounded fragments of quartz, kieselschiefer, and 



* Rothes todtes liegendc, or celtester jltxtzsandstein of the 

 school of Freyberg ; poudingue psammitique of Messrs. Brong- 

 niart and Bonnard. 



+ Muldenformige lageriing, 



I At Malpasso and Piedras Azules. See above* p* 



