64 TRAVELS AMONGST THE GREAT ANDES, chap. hi. 



through the shattered lava behind it, crossed the arete and 

 emerged on the western side of the ridge. There was then the 

 view before ns that is given on the opposite page. The western 

 dome, which had been hidden during part of the ascent, again 

 became conspicuous ; crowning wall-like cliffs of lava, that grew 

 more and more imposing as we advanced. As regards the western 

 summit, there are two series of these cliffs — the upper ones imme- 

 diately underneath the dome, surmounted by sheer precipices of 

 ice, and the lower ones at the end of a spur thrown out towards 

 the south-west. '^I'hese lower cliffs are neither so extensive nor as 

 perpendicular as the upper ones,^ and they are crowned by snow, 

 not by glacier. Our ridge led up to their base, and at the junction 

 there was a want of continuity rather than a distinct breach in 

 the walls. ^ This was the spot which, when examining the mount- 

 ain on Dec. 21, at a distance of sixteen miles, we had unani- 

 mously regarded as the critical j^oint, so far as an ascent was 

 concerned (see pp. 25, 26). 



Up to this place the course was straightforward. In the imme- 

 diate foreground, and extending upwards for 500 or 600 feet, large 

 beds of snow^ in good condition covered the ridge. The pinnacle 

 or aiguille near at hand was upon the arete or crest of it, and 

 the two others shewn in the engraving upon p. 41 were higher 

 up on the right hand or eastern side. The ridge itself appears 

 to be fundamentally an old flow of lava. Rock specimens which 

 were taken in situ at various elevations, though differing to some 

 extent in external appearance, are nearly identical in composition,^ 

 and I have no doubt that several, at least, of the other principal 



1 The}^ are seen in the view facing p. 24, which is talcen from almost precisely 

 the same direction as that facing this page, though at a much lower level. 



2 Marked Z on the Sketch plan of part of the Southern side of Chimhorazo. 



3 " This rock (from the second camp, in situ) is a dullish lavender-grey colour, 

 with crystals of glassy felspars up to about 4 inch long, and some minute blackish 

 specks, which weather rather a reddish colour. I think it very probable that a 

 little sanidine is present among the felspars. The rock is a variety of the hyper- 

 stheniferous augite-andesites. 



