1835.] Ascent of Chimhorazo. 261 



on our return to Rio Bamba. In the midst of the sandy 

 soil which occupies the whole plain of Rio Bamba, we ob- 

 serve, near the village of Calpi, an eminence of a deep 

 colour. It is Jana, Urea, (the Black Mountain.) In the 

 lower part of this small hill, the trachyte may be observed 

 passing from under the sand. It is of the same nature as 

 that which supports Chimhorazo . This trachyte appears to 

 have been strongly acted on, being full of crevices. The 

 top of Jana, Urcu, which looks to Calpi, is formed of small 

 fragments of the black rock. It reminds us of the erup- 

 tion of Lysco. It would appear, even, that at Jana Urcu, 

 this eruption took place after the deposition of the sand 

 which whitens the plain ; for its surface, in the vicinity of 

 the volcano, is strewed with these black scoriform stones. 



Our guides, who were Indians of Calpi, conducted us to 

 a crevice where we distinctly heard the sound of a subter- 

 ranean cascade, and, judging by the noise, the mass of water 

 which produced it must have been considerable. . The barren- 

 ness of the soil, from Latacunga to Rio Bamba, had several 

 times astonished me. I asked, how do the glaciers, the 

 elevated mountains, which overhang this soil, not produce 

 numerous torrents? The dryness of the plateau is only 

 superficial. It appears certain that the waters of the moun- 

 tains, after having penetrated into the ground, circulate at 

 a greater or less depth in the interior of the earth. The 

 subterraneous cascade of Jana Urcu is a decided proof; and 

 in several places, while descending the deep chasms which 

 furrow the alluvial soil of the plateau, numerous springs of 

 water may be observed. 



Near Latacunga, between that town and Cotopaxi, there 

 exists a depot of water, which was encountered by digging 

 some yards deep in the conglomerate pumice-stone. It is 

 called, by the Indians, Tombo Polio. In fact, it is a stream 

 of subterranean water ; the water is incessantly renewed, 

 and a current can be distinctly perceived. I found its tem- 

 perature 18'°8, (65-°8.) The temperature of Latacunga is 

 15-°5 C. (60°) 



On the 21st December, we were, on our return, at Rio 

 Bamba, where I still rested some days to complete my 

 observations. On the 23d, after noon, I left Rio Bamba for 

 Guayaquil, to embark for the coast of Peru. It was in view 



