58 Geological DeUneaf ion of Soul k America. 



(anses) which proceed from east to west in the direction of 

 the tropical current, and on that account extend further 

 into the land the broader the continent is. The vallevs of 

 Apure and Orinoco are closed by the ridge which extends 

 from Pampelona to Merida in longitude 73°, and the val- 

 ley of Pampas in longitude 70*' : the,y both fall together a 

 little towards the east, and seem to be covered by one and 

 the same formation of alluvial strata. 



Trades says, that in Swisserland there is more reason to 

 wonder at the depth of the lakes than at the height of the 

 mountains: I will venture to make a similar observation in 

 regard to the IJancs or plains of South America. How 

 astonishing it is to see a continent which in its inte- 

 rior parts several hundred miles from the coast, and in the 

 neighbourhood of moimtains 3000 toises in lieight, is ele- 

 vated scarcely fifty toises above the surface of the sea ! If 

 the flux in these places should rise to as great a height as 

 at St. Malo and Bristol, and if more motion should be 

 communicated to the ocean bv earthquakes, the greater 

 part of these valleys would be laid under water. The 

 highest Llano which I have measured is that between the 

 rivers Ymirida, Temi, Pimichia, Cassiguiare, and Guiainia 

 (Rio Negro) ; il is ISO toises in heiglit ; but it sinks down 

 towards Alures in the north, as towards the river Amazon 

 in the south. The valley of Orinoco and Apnrc is still 

 nuich lower than that of Cassicuiare and C'alabozo in the 

 middle of the Llano where I made observations, in latitude 

 6° 56' 56" and longitude 70° 9' west from Paris. At An- 

 gostura, the capital of Guyana, latitude S° 8' 24", lonaitude 

 {)6°, it is only 33 toises, and eighty miles from the coast 

 scarcely eight toises above the level of the sea. The plains 

 of Lombardy, in Europe, have the greatest resemblance to 

 the Llanos on account of their small elev^ation. Pavia is 

 only 34, and Cremona 24 toises in height; the other plains 

 of Europe have a much greater elevation. h\ Saxony and 

 Lower Silesia the plains are only from 87 to 120 toises 

 )n height ; those of Bavaria and Swabla are from 230 to 

 250. The declivity of the Llanos of America is so gentle, 

 their inequalities are so imperceptible, that no large river 

 flows to either side. The Orinoco appears in the longitude 

 of about 70", as if about to discharge itself in the sea towards 

 Portobello ; but at Cabrouta it turns to the east without the 

 least obstacle being discovered either there or at St. Fernando 

 de Atabapo, in latitude 7° 55' 8", to oppose its course. In 

 the large valley (f Rio Negro, and of the Amazon rjver, i55 

 * tract of land, in 2° or 3° north latitude, of not less thaa 



1600 



