128 Prof. T. G. Bonney. On the [June 19, 



of Alum Bay. It was impossible to collect these in situ, the cliffs 

 being well-nigh perpendicular; but specimens from all the strata 

 were broken off by the ice falling from the glaciers above, and fell 

 along with the ice on to the Glacier de Debris below. From the 

 surface of this glacier I collected numerous specimens, and they 

 embrace most of the varieties of rock to be found on the mountain. 

 Amongst this debris was found a small fragment of native sulphur. 



" There is a prominent and important ridge leading from the second 

 summit in a south-south-westerly direction. Our second and third 

 camps (16,600 and 17,300 feet respectively) at which we passed 

 sixteen days and nights, were established on this ridge, which starts 

 from the foot of the above-mentioned cliffs and extends right down to 

 the arenal grande. The specimens collected in situ from the rocks at 

 the second and third camps are nearly identical in nature. 



" Our fourth camp (14,400 feet) was established on the southern 

 side of a very prominent lava stream that starts high up on the 

 mountain on its northern side, which at its commencement descends a 

 little to the east of north, and in its lower course bends round towards 

 the west; and our fifth camp (15,950 feet) was placed about two 

 miles to the south-west of the last named, against some large blocks 

 of lava. 



" On the southern side of the mountain there are numerous masses 

 of scoria lying about, in the same manner as is seen around the active 

 volcano Cotopaxi, which may either have been ejected from Chimbo- 

 razo when it was in a state of activity, or have fallen from its decom- 

 posing beds. The whole of the western side of the mountain (which 

 has, I believe, scarcely been visited by earlier travellers) was found 

 between about 13,000 and 15,000 feet to be covered by vast sandy 

 plains. 



" It was observed during our sojourns upon and in the neighbour- 

 hood of Chimborazo in the months of December, 1879, and January, 

 June, July, 1880, that easterly and north-easterly winds were of most 

 frequent occurrence. These winds usually brought bad weather, and 

 much snow fell while they lasted. To this preponderance of easterly 

 and north-easterly winds I attribute the great development of glacier 

 which is found upon those sides of the mountain, and the occurrence 

 of the vast sandy plains which exist on the western or lee side. The 

 sand is drifted entirely away from the eastern slopes, which, at the 

 corresponding elevation of 13,000 to 15,000 feet, are rugged, fissured, 

 and often troublesome to traverse. The western side, at these eleva- 

 tions, is free from difficulty. All fissures and minor inequalities 

 are completely effaced, and in the month of July, without any guide 

 except the barometer and compass, we made the circuit of the moun- 

 tain at about the level of 14,000 feet, and struck with certainty the 

 exact spot upon the arenal yraiide at which we desired to arrive. 



