318 REACTION OF THE INTERIOR OF THE EARTH 



connection of the two Cordilleras by mountain knots 

 and mountain walls or dikes (sometimes low like the 

 Altos de Chisinche, just mentioned ; and sometimes as 

 high as Mont Blanc, as over the Passo del Assuay) 

 appears to be a more recent, and also a less important, 

 phenomenon, than the elevation of the parallel chains 

 themselves. As Cotopaxi, the greatest of all the Quito 

 volcanoes, presents, in its trachytic rock, many analogies 

 with Antisana, so also we find on the slopes of Cotopaxi, 

 lines of rocky fragments similar to those which have 

 occupied us above, and more numerous. 



We felt a great desire to trace up these lines of 

 fragments to their origin, or rather to the place where 

 they are hidden under the covering of perpetual snow. 

 We ascended on the south-west slope of the mountain, 

 from Mulalo (Mulahalo), by the side of the Rio Alaques, 

 which is formed by the Rio de los Banos, and the Rio 

 Barrancas, to Pansache (12,066 feet high), where we 

 occupied the roomy Casa del Paramo, on the grassy 

 plain el Pajonal. Although much snow had fallen 

 sporadically at night, we succeeded, keeping to the east 

 of the celebrated Cabeza del Inga, in arriving, first at 

 the Quebrada and Reventazon de las Minas, and sub- 

 sequently, keeping still more to the east, over the 

 Alto de Suniguaicu, at the Ravine of the Lion's Mount 

 (Puma Urcu), where the barometric readings gave an 

 elevation of 14,470 feet. Another line of fragments, 

 which, however, we only saw from a distance, ran from 

 the eastern part of the snow-covered cone of cinders, 

 towards the Rio Negro (a tributary of the Amazons), 

 and towards Valle Vicioso. Whether these blocks, 

 which we suppose to have been glowing masses of 



