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



tions on its summit, is 15,870 feet.* I have frequently seen its 

 entire eastern side quite free from snow, but there are upon its 

 opposite, or western, side some large snow-beds and couloirs which 

 are apparently permanent. The mountain therefore just enters the 

 snow-line. 



" The summit ridge is a great wall, about 250 feet long, running 

 (approximately) north and east-south-east, having a sheer precipice on 

 its western, and a very steep cliff on its eastern side. Possibly this 

 wall should be regarded as a dyke. There is no regularly formed 

 crater upon any part of the mountain. 



" On the summit ridge I collected specimens of rock in situ, and of 

 debris lying upon it. The crest of the ridge was almost covered by 

 rock debris and earth. Flowering plants were growing up to the 

 very highest point, and vegetation near the summit was more 

 abundant than was found at equal heights on any of the other 

 Ecuadorian Andes." (E. W.) 



From the upper part of Corazon Mr. Whymper has brought eleven 

 specimens. Of these, ten were taken from debris scattered about on 

 the summit ridge, and one was broken from the highest rock in 

 situ. 



The last is a scoriaceous rock with many small cavities and 

 vesicles, darkish grey, slightly inclining to brown in colour. The 

 microscope shows that there is present a fair amount of a glassy 

 base, with a brown staining. This base contains numerous acicular 

 colourless crystallites, and spots often rather elongated of opacite, 

 which not seldom are clustered together, and form a kind of frame to 

 the larger felspar crystals. These last are rather abundant, and very 

 commonly do not exceed about '02 inch diameter, though they are 

 occasionally considerably larger, four or five times the size. The 

 latter often have the dirty look described above. The slide contains 

 a few grains of a pyroxenic mineral, not very distinctly characterised. 



The ten specimens gathered at different localities on the summit 

 ridge of Corazon afford the following varieties: 



(A.) A grey pumiceons rock, larger vesicles, a little more than 

 1 inch diameter: volume of solid part and hollows about equal : with 

 this may be classed a rather less vesicular specimen, with small 

 felspar crystals; both these have a tendency to weather brown. 



(B.) Four specimens of more or less scoriaceous rock of a purplish 

 colour within, weathering externally to an Indian-red colour, and con- 

 taining specks of white felspar. 



(C.) Two specimens of dull grey rock with a rough fracture, 

 speckled with small felspar crystals, and with a spotted look, one 

 being more decomposed than the other. 



* By A Messrs. Reiss and Stubel made its height 15,801 feet. 



