241 



journey over Assuay is formidable, especially in 

 the months of June, July, and August, when 

 there are immense falls of snow, and the icy 

 winds of the south sweep over these regions. 

 As the high road, according to the measures I 

 took in 1802, is almost the height of Mount 

 Blanc, the travellers are exposed to a cold so 

 excessive, that several perish every year from its 

 effects. In the middle of this journey, at the ab- 

 solute height of four thousand metres, we cross 

 a plain, the extent of which is six square 

 leagues. This plain (and this remarkable fact 

 throws some light on the formation of elevated 

 plains) is almost on the level of the savannahs, 

 by which the part of the volcano of Antisana 

 covered with eternal snows is surrounded. The 

 elevated plains of Assuay and of Antisana, the 

 geological construction of which has such strik- 

 ing resemblances, are nevertheless more than 

 fifty leagues distant from^ach other : they con- 

 tain lakes of fresh water of considerable depth, 

 and bordered by a thick turf of Alpine grasses, 

 but no fish, and scarcely any aquatic insect, en- 

 livens their solitude. 



The soil of the Llano del Pullal, the name 

 given to the high plains of Assuay, is excessively 

 marshy. We were surprised to find in this 

 place, and at heights which greatly surpass the 

 top of the Peak of TenerifFe, the magnificent re- 



VOL XIII. R 



