CHAP. XIV. 



ON THE SUM31IT OF COTOCACIIL 



263 



the snow, and to the greater steepness of the ground.^ I noticed 

 that 657 steps were made without stopping, when between 

 15,000-16,000 feet high ; and this compares favourably with the 

 experiences of many practised mountaineers at a similar elevation 

 (pressure) upon Mont Blanc. Though it must be admitted that 

 the steps were short ones 

 (as we were quite unable 

 to do anything approach- 

 ing this during the earlier 

 part of the journey), there 

 is reason to believe that 

 we had, in the course 

 of the last four months, 

 become somewhat habit- 

 uated to low pressures. 



The true summit of 

 Cotocachi is a pointed 

 peak of lava,'^ broken up 

 by frost, extremely steep 

 at the finish, and upon 



that account bearing little snow. I estimate it to be 150 to 180 

 feet higher than the northern, or second summit. This mountain 



COTOCACHI, FROM CARRANQUI 



^ Left camp at 8.25 a.m., and went to the top without a halt. On the 24th of 

 April, at 12 (noon), the Mercurial Barometer (reduced to 32° Faht.) read 16-661 

 inches, air temperature 36°-5 Faht. The 11 a.m. observation at Guayaquil (red. to 

 32°) was 29-869 inches, air temp. 81° Faht. 



2 "Purplish-grey rock, containing small whitish felspar crystals, with a good 

 many minute vesicles. . . The ground mass appears to consist of a glassy base, 

 containing minute crystallites, probably for the most part felspar, but perhaps also 

 a pyroxenic mineral, with rods of opacite and with ferrite staining. In this occur 

 crystals of plagioclastic felspar, not generally exceeding 0-3 inch, agreeing in general 

 character with those already described, but perhaps more frequently containing 

 enclosures, and 'dirty looking,' together with a pyroxenic mineral. The crystals 

 of this are not very characteristic, but I think both augite and hypersthene can be 

 identified. . . These rocks from Cotocachi appear to be hyperstheniferous augite- 

 andesite."— Prof. T. G. Bonney, Proc. Royal Soc, Nov. 27, 1884. 



