ON ITS EXTEBIOK. VOLCANOES. 295 



de Ario, which Bonpland and I found decked with the 

 since then so well-known flowers of the dahlia, we have 

 not yet lessened the altitude a thousand feet. But when 

 we pass from Ario, on the steep declivity above Agua- 

 sarco, to the level of the old plain of Jorullo, in that 

 very short distance we diminish the absolute height 

 about 4000 feet.( 431 ) The round convex part of the 

 upheaved plain is about 12,800 feet across. The vol- 

 cano of Jorullo itself, and the five other mountains which 

 rose together with it upon the same fissure, are so 

 placed that only a small part of the Malpais falls to 

 the east of them. The number of hornitos is therefore 

 much greater on the western side ; and when in the 

 early morning I came out of the Indian hut in which I 

 had passed the night, in the Playas de Jorullo, or when 

 I ascended a part of the Cerro del Mirador, I saw the 

 black volcano rise very picturesquely above the count- 

 less columns of white smoke issuing from the hornitos 

 (the little ovens or furnaces). Both the houses of the 

 playas and the basaltic hill Mirador are on the level of 

 the ancient unvolcanic or, to speak more cautiously, 

 not upheaved ground. The beautiful vegetation, in 

 which a host of salvias bloom under the shadow of a 

 new kind of fan palm (Corypha pumos) and a new kind 

 of alder (Alnus jorullensis), contrasts with the desert 

 nakedness of the Malpais. The comparison of the 

 height of the barometer ( 43 ^) at the point where the 

 upheaving in the playas begins, to a point situated 

 immediately at the foot of the volcano, gives a differ- 

 ence of 473 feet. The house which we inhabited 

 stood about 3200 feet from the edge of the Malpais. 

 This edge is a small vertical precipice only twelve feet 



