248 Prof. Bonney : Penological Notes on the Euphotide 



and for some distance below it the latter rock is certainly 

 much the more abundant*. The euphotide certainly is the 

 more durable rock, but I do not think that a " survival of the 

 fittest" is a sufficient explanation, and can only suppose that 

 the smaragdite-euphotide predominated in the part of the 

 mass which has been removed. 



(b) The second matter seems to me a still greater difficulty. 

 These blocks occur in countless thousands. To speak only of 

 the valley above Saas-im-grund, the part which I have 

 examined most closely, they abound in every wall, and are 

 strewn thickly over many acres of land by the side of the 

 torrent. It is, I believe, no exaggeration to say that they 

 constitute one fourth of the boulders ; often 3 or 4 may be 

 seen actually touching one another ; not seldom their volume 

 is 2 or 3 cubic feet, often much more than a cubic yard. 

 But, as I have already indicated, the parent mass of rock is 

 rather small. Its surface, compared with that of the ridges 

 and crags which pay tribute to the Hochlaub, Allalein, 

 Schwartzenberg, and other glaciers is almost insignificant. 

 An explanation might be suggested on the principle that 

 " you cannot spend and have ; " the gabbro mass may have 

 impoverished itself by a lavish distribution of boulders, so 

 that what we now see may be only a residual fragment of the 

 original ridge. Such an answer, however, in reality increases 

 rather than removes the difficulty. These boulders for the 

 most part were distributed when the Alpine glaciers were 

 much larger than at present. Add only fifty feet to the 

 thickness of the ndvd, and the height of the ridge would be 

 seriously diminished, while the two small neighbouring out- 

 crops would, I believe, be buried. But the form of the ridge 

 is such that there are difficulties in understanding how the 

 height could be materially increased. It is like a wedge 

 resting on the broader end, the crest being at most only a 

 few feet wide, and its craggy sides are everywhere rather 

 steep. It is my impression (and this accords with the map) 

 that the greatest breadth of the base does not exceed a hundred 

 yards. It would be difficult to pile up more than about ten 

 thousand cubic yards of rock upon the present mass, yet the 

 volume of the scattered blocks must greatly exceed thisf. 



* I infer from Capt. Marshall Hall's account that there was at any rate 

 a considerable quantity of the hornblendic variety in the eastern crags. 



t It might be suggested that the ridge was once longer and that the 

 front part has been removed by denudation ; but if so, and if the removal 

 was effected when the glaciers were larger, we ought now to see a low 

 spur exposed — the foundation of the portion removed — rising above the 

 ice at the base of the crag at the eastern end. 



