ILLUSTRATIONS (4). THE LLANOS. 20 



part of China, such rocky banks are termed Tsy. In the 

 woody plains of the Orinoco they are found to be surrounded 

 with 'the most luxuriant vegetation.* In the midst of these 

 flat, tabular masses of granite and syenite, several thousands 

 of feet in diameter, presenting merely a few scattered lichens, 

 we find in the forests, or on their margins, little islands of 

 light soil, covered with low and ever-flowering plants, having 

 the appearance of small gardens. The monks settled on the 

 Upper Orinoco, singularly enough regard the whole of these 

 horizontal naked stony plains, when extending over a consi- 

 derable area, as conducive to fevers and other diseases. Many 

 of the villages belonging to the mission have been transferred 

 to other spots 011 account of the general prevalence of this 

 opinion. Do these stony flats (laxas] act chemically on the 

 atmosphere or influence it only by means of a greater radiation 

 of heat? 



(5) p. 2 "Compared with the Llanos and Pampas of South 

 America, or even with the Prairies on the Missouri" 



Our physical and geognostic knowledge of the western 

 mountain region of North America has recently been enriched 

 by the acquisition of many accurate data yielded by the 

 admirable labours of the enterprising traveller Major Long, 

 and his companion Edwin James, but more especially by the 

 comprehensive investigations of Captain Fremont. The 

 knowledge thus established clearly corroborates the accuracy 

 of the different facts which in my work on New Spain I could 

 merely advance as hypothetical conjectures regarding the 

 northern plains and mountains of America. In natural his- 

 tory, as well as in historical research, facts remain isolated 

 until by long-continued investigation they are brought into- 

 connection with each other. 



The eastern shore of the United States of North America 

 inclines from south-west to north-east, as does the Brazilian 

 coast south of the equator from the Rio de la Plata to Olinda. 

 on both these regions there rise, at a short distance from the 

 coast line, two ranges of mountains more nearly parallel to 

 each other than to the western Andes, (the Cordilleras 

 If Chili and Peru), or to the North Mexican chain of the 

 Rocky Mountains. The South American or Brazilian moun- 

 * Relation Hist., t. ii., p. 279. 



