611 



The petroleum, and this phenomenon is well 

 worthy of attention, issues from a soil of mica- 

 slate in the gulph of Cariaco (Vol. ii, p. 290). 

 If, further east, on the banks of the Arco (Vol. 

 iii, p. 97; Vol. iv, p. 51), and near Cariaco 

 (Vol. ii, p. 216, 290), it seems to gush from 

 secondary limestone formations, it is probably 

 only because those formations repose on mica- 

 slate (Vol. vi, p. 97). The hot springs of Vene- 

 zuela have also their origin in, or rather below, 

 the primitive rocks. They issue from granite 

 (Las Trincheras), gneiss (Mariara and Onoto), 

 and the calcareous and arenacious rocks that 

 cover the primitive rocks (Morros de S. Juan, 

 Bergantin, Cariaco). The earthquakes and 

 subterraneous detonations, of which the seat 

 has been erroneously sought in the calcareous 

 mountains of Cumana, have been felt with most 

 violence in the granitic soils of Caraccas, and 

 the Oroonoko (Vol. iv, p. 24, 45). 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 (Vol. 

 iii, p. 83 ; Vol. v, p. 550, 551). 



From the whole of these observations, it re- 

 sults, that gneiss-granite predominates in the 

 immense groupe of the mountains of Parime, 

 as micaslate-gneiss does in the Cordillera of the 

 shore ; that in the two systems, the granitic 



2 s 2 



