1841.] VEINED STRUCTURE ON THE GLACIER OF THE RHONE. 7 



the last-named valley, it spreads itself across and along it 

 pretty freely much as a pailful of thickish mortar would do in 

 like circumstances. The form into which it spreads is rudely 

 represented in the annexed figure. In this particular case, 

 even the strongest partisans of the dilatation theory will 

 hardly deny, that the accumulated ice descending from the 

 glacier cataract A would form a centre of pressure at C, and 

 that the lines of equal pressure 

 would be found in the direction of 

 the dotted lines, following nearly 

 the periphery of the glacier. Now 

 these dotted lines precisely trace 

 out the course of the veined struc- 

 ture alluded to ; and, moreover, 

 they bend more and more forwards 

 as we proceed from the centre of 

 pressure C, especially in the direc- 

 tion of D, the line of greatest in- 

 clination of the bed, and down 

 which gravity urges the icy mass. 

 The front of the glacier, about E D 

 F, presents the fallacious apearance 

 of horizontal strata, as in the Aar glacier ; but these are found 

 to dip inwards at an angle of 10 or 15, which angle continually 

 increases as we approach the heart of the glacier, rising to 40, 

 50, 60, and even 70, as we approach C. It cannot be 

 doubted, that these facts are so far favourable to the view which 

 we have taken, although the establishment of it would require 

 far more extensive observation ; and in several glaciers which I 

 have visited, the observation of the convolutions of the veined 

 structure is very difficult and obscure. Before quitting the sub- 

 ject, I must add an observation which I made on the Glacier 

 of the Rhone, arid which I am pretty confident is well founded. 

 The lines of fissure, or crevasses, are always perpendicular to 

 the conical surfaces of the veined structure. These fissures are 

 denoted in the figure by the % full lines a a a. Perhaps the 



Moraines 



cut by the 

 River. 



The Rhone. 



