312 COSMOS. 



ed cone lying toward the north. In the plateau, partly des- 

 ert and sandy, partly covered with grass (the dwelling-place 

 of a very spirited race of cattle, which, owing to the slight 

 atmospheric pressure, easily expel blood from the mouth and 

 nostrils when excited to any great muscular exertion), is sit- 

 uated a small farm (hacienda), a single house in which we 

 passed four days in a temperature varying between 38*6. 

 and 48-2. The great plain, which is by no means cir- 

 cumvallated as in craters of elevation, bears the traces of an 

 ancient sea-bottom. The Laguna Mica, to the westward of 

 the Altos de la Moya, is fb be regarded as the residue of the 

 old covering of water. At the margin of the limit of per- 

 petual snow the Rio Tinajillas bursts forth, subsequently, 

 under the name of Rio de Quixos, becoming a tributary of 

 the Maspa, the Napo, and the Amazon. Two narrow, wall- 

 like dikes or elevations, which I have indicated upon the 

 plan of Antisana, drawn by me, as coulees de laves, and which 

 are called by the natives Volcan de la Hacienda and Yana 

 Volcan (Yana signifies black or brown in the Qquechhua 

 language), pass like bands from the foot of the volcano at 

 the lower margin of the perpetual snow-line, and extend, ap- 

 parently with a very moderate declivity, in a direction N.E. 

 S.W., for more than 2000 toises (12,792 feet) into the 

 plain. With very little breadth they have probably an ele- 

 vation of 192 to 213 feet above the soil of the Llanos de la 

 Hacienda, de Santa Lucia, and del Cuvillan. Their decliv- 

 ities a$e every where very rugged and steep, even at the ex- 

 tremities. In their present state they consist of conchoidal 

 and usually sharp-edged fragments of a black basaltic rock, 

 without olivin or hornblende, but containing a few small 

 white crystals of feldspar. The fundamental mass has fre- 

 quently a lustre like that of pitch-stone, and contains an ad- 

 mixture of obsidian, which was especially recognizable in 

 very large quantity, and more distinctly in the so-called 

 Cueva de Antisana, the elevation of which we found to be 

 15,942 feet. This is not a true cavern, but a shed formed 

 by blocks of rock which had fallen against and mutually 

 supported each other, and which preserved the mountain 

 cowherds and also ourselves during a fearful hail-storm. 

 The Cueva lies somewhat to the north of the Volcan de la 

 Hacienda. In the two narrow dikes, which have the ap- 

 pearance of cooled lava streams, the tables and blocks ap- 

 pear in part inflated like cinders, or even spongy at the 

 edges, and in part weathered and mixed with earthy detritus. 



