l:;i' Prof. T. G. Bonney. On the [June 19, 



called Abraspungo (14,479), and its northern slopes extend almost to 

 the town of Ambato (8,500). The road to Quito winds round it 

 eastern side, and may be considered to mark its boundaries in that 

 direction. 



" It is stated by historians that this mountain was formerly loftier 

 than Chimborazo, and that a portion of its apex fell during a great 

 earthquake which occurred at the end of the 17th century. I saw 

 nothing to lead me to suppose that the mountain was at any time 

 much loftier than at present, though it appears beyond dispute that a 

 great fall actually occurred at the above-mentioned period. The part 

 which fell may have formed the northern and eastern side of its 

 crater. At the present time the three peaks which are upon its 

 summit ridge are disposed in a horseshoe form, and I conjecture 

 formed the southern and western sides of a crater which is now 

 buried underneath glaciers. 



" We ascended the middle peak of these three, and by mercurial 

 barometer found that its height was 16,514 feet. Messrs. Reiss and 

 Stiibel by A calculated the height of Carihuairazo to be 16,752 feet. 

 They, however, probably measured the most eastern of the three 

 peaks, which is actually somewhat loftier than the central one. 



" The lower slopes of this mountain are very swampy, from which it 

 may be conjectured that there are not so many fissures in the soil as 

 is common in the Ecuadorian Andes, and large thickets of trees, some 

 of considerable age, grow high up its flanks, from which it is reason- 

 able to conclude that it is long since the mountain was an active 

 volcano. The rocks at the time of our expedition were much covered 

 up by snow in the higher regions, and by earth and vegetation on 

 the lower slopes. Such rocks as were exposed appeared closely allied 

 to the specimens collected upon Chimborazo and the other mountains, 

 and we only brought away specimens from the summit of the central 

 peak. These were taken close to its highest point." (E. W.) 



The rock appears to be pretty evenly jointed, it weathers brown, and 

 breaks with a rather rough irregular fracture. The colour on this is a 

 warm purplish-grey mottled with darker spots, and speckled with 

 small rather light coloured crystals of felspar with a rather satiny 

 lustre. A few minute vesicles may be perceived under the microscope. 

 The larger felspar crystals in the slide are rather numerous, and 

 commonly vary from about '05 to '07 inch in the longer diameter. 

 They exhibit well developed polysynthetic twinning, and are 

 labradorite or a closely allied form. Enclosures of glass or various 

 microliths are occasionally seen, but the majority of the crystals are 

 fairly clear, though a few are very dirty, and have a corroded look at 

 the exterior. There is also present in the ground-mass a fair number 

 of crystals of angite of a yellowish-green colour, not exceeding about 

 "03 inch in length, and two or three which in structure, dichroism, 



