22 EIO DE AQUAS CALIENTES. 



Cura towards its source, the mountains of Mariara are seen 

 advancing into the plain in the form of a vast amphitheatre, 

 composed of perpendicular rocks, crowned by peaks with 

 rugged summits. The central point of the amphitheatre 

 bears the strange name of the Devil's Nook (Eincon del 

 Diablo). The range stretching to the east is called El 

 Chaparro ; that to the west, Las Viruelas. These ruin-like 

 rocks command the plain ; they are composed of a coarse- 

 grained granite, nearly porphyritic, the yellowish white feld- 

 spar crystals of which are more than an inch and a half long. 

 Mica is rare in them, and is of a fine silvery lustre. Nothing 

 can be more picturesque and solemn than the aspect of this 

 group of mountains, half covered with vegetation. The 

 Peak of Calavera, which unites the Eincon del Diablo to the 

 Chaparro, is visible from afar. In it the granite is separated 

 by perpendicular fissures into prismatic masses. It would 

 seem as if the primitive rock were crowned with columns of 

 basalt. In the rainy season, a considerable sheet of water 

 rushes down like a cascade from these cliffs. The moun- 

 tains connected on the east with the Eincon del Diablo, 

 are much less lofty, and contain, like the promontory of La 

 Cabrera, and the little detached hills in the plain, gneiss 

 and mica-slate, including garnets. 



In these lower mountains, two or three miles north-east 

 of Mariara, we find the ravine of hot waters called Que- 

 brada de Aguas Calientes. This ravine, running JN".W. 75, 

 contains several small basins. Of these the two uppermost, 

 which have no communication with each other, are only 

 eight inches in diameter ; the three lower, from two to three 

 feet. Their depth varies from three to fifteen inches. The 

 temperature of these different funnels (pozos) is from 56 

 to 59 ; and what is remarkable, the lower funnels are 

 hotter than the upper, though the difference of the level 

 is only seven or eight inches. The hot waters, collected 

 together, form a little rivulet, called the Eio de Aguas 

 Calientes, which, thirty feet lower, has a temperature of only 

 48. In seasons of great drought, the time at which we 

 visited the ravine, the whole body of the thermal waters 

 forms a section of only twenty-six square inches. This is 

 considerably augmented in the rainy season ; the rivulet is 

 then transformed into a torrent, and its heat 



