Ejection of Stones — Crevasses. 153 



structure, and they are finally dispersed on the surface by 

 the melting of the ice. What is here supposed to occur is 

 illustrated by an ideal section of the glacier of the Rhone, 

 Plate II., fig. 7, where the curves of ejection are identical 

 with those oi forced separation, causing the frontal dip of the 

 veined structure ; and this view is confirmed by what I have 

 often observed, particularly on the Glacier of Bossons, that 

 the veined structure in contact with the lateral moraines 

 becomes soiled, and that dirt and stones may be traced along 

 the course of the structural bands from the moraine to a con- 

 siderable depth in the ice. The action there is in the hori- 

 zontal plane, what we here suppose to take place in the ver- 

 tical, and which the now established retardation of the lower 

 strata permits us to assume as exactly a similar action. I 

 have no doubt that a similar explanation applies to the gla- 

 cier of the Nant Blanc, and to other glaciers.* 



Before closing this already too long letter, I wish to record 

 an observation already made by me in 1844, but which I 

 hesitated to publish because the sketch representing it was 

 made from memory, and not upon the spot ; but I have now 

 verified it both in the same and another locality. It is re- 

 presented in Plate II., fig. 5, where h di^ part of the wall 

 of the glacier, which is about to turn at a considerable angle 

 with its former direction (it is at the well-known part of the 

 Mer de Glace named V Angle), I knew, from long experi- 

 ence, that the ice here presents, year after year, compact 

 ridges, such as o 6, c d, parallel to one another, and separated 

 by a mass of crevasses which it is, generally speaking, impos- 

 sible to cross ; and any one who attempts to traverse the 

 more crevassed portions of the glacier without attending to 

 this peculiarity, will infallibly lose his w^ay. But, as the 

 drawing explains, the direction of these ridges by no means 



* It will be seen that this explanation will give an elevatory force to the ice 

 containing blocks similar to that which De Charpentier (Essai sur les Glaciers, 

 § 25) ascribed to the expansion of the frozen water. It will also be seen that 

 it renders a perfect account of the " veins of the debris of rocks" in glaciers, 

 particularly near their lower extremitic!?, which that ingenious author has at- 

 tempted to account for (unsatisfactorily, I think) by the transporting action of 

 streams of water. — {Hid., % 27). 



