THE "GREAT 1HE AdE'' 137 



this mountain the journey from the lower ice-wall of the 

 Glacier de Bessons up to the bergschrund above the Grand 

 Plateau is over one continuous ice-field, the level of the 

 upper part of which is more than 10,000 feet above its ter- 

 minal ice-wall. Thus, if we take the height of the stria- 

 ations or smoothings of the upper neve above the low 

 grounds on which the ice-sheet rests, and adopt Mr. Geikie's 

 reasoning, the lower ice- wall, of the Glacier de Bessons 

 should be 10,000 feet thick. Its actual thickness, as nearly 

 as I can remember, is about 10. or 12 feet. 



Every other known glacier presents the same testimony. 

 The drawing of a Greenland glacier opposite page 47 of 

 Mr. Geikie's book shows the same under arctic conditions, 

 and where the ice- wall terminates in the sea. 



I have not visited the Hebrides, but the curious analogy 

 of their position to that of the Lofodens suggests the de- 

 sirability of similar observations to those I have made in 

 the latter. If the ice between the mainland and the Outer 

 Hebrides was, as Mr. Geikie maintains, "certainly more 

 than 2000 feet in thickness," and this stretched across to 

 Ireland, besides uniting with the still thicker ice-sheet of 

 Scandanavia, these islands should all be glaciated, especially 

 the smaller rocks. If I am right, the smaller outlying 

 islands, those south of Barra, should, like the corresponding 

 rocks of the Lofodens, display no evidence of having been 

 overswept by a deep "mer de glace." 



I admit the probability of an ice-sheet extending as Mr. 

 Geikie describes, but maintain that it thinned out rapidly 

 seaward, and there became a mere ice-floe, such as now im- 

 pedes the navigation of Smith's Sound and other portions 

 of the Arctic Ocean. The Orkneys and Shetlands, with 

 which I am also unacquainted, must afford similar crucial 

 instances, always taking into account the fact that the 

 larger islands may have been independently glaciated by the 

 accumulations due to their own glacial resources. It is the 

 small rocks standing at considerable distance from the 

 shores of larger masses of land that supply the required 

 test-conditions. 



From the above it will be seen that I agree with Mr. 

 Geikie in regarding the till as a "moraine profonde," but 



