1850.] PASS OF THE COL DU TOtJfc. 227 



Le Tour are separated throughout by a rocky ridge, but the 

 Glaciers of Le Tour and Trient all but unite at their highest 

 parts, and the main chain is prolonged with scarcely a break in 

 the north-east direction, sending off only a spur towards the 

 Col de Balme, which, perhaps from being the political boundary 

 of Savoy and Switzerland, has been represented generally on 

 an exaggerated scale. What surprised me most, was the great 

 elevation of the axis of the chain at the head of the Glaciers of 

 La Tour and Trient. I found it barometrically to be 4044 feet 

 above the chalet of the Col de Balme, which, from five com- 

 parisons made with the observatory at Geneva, is 7291 English 

 feet, or 2220 metres above the sea, a result agreeing closely 

 with the recent measurement by M. Favre, which is 2222 

 metres. Adding this result to the former, we obtain 11,335 

 English feet for the height of the granitic axis at the lowest 

 point between the Glaciers of La Tour and Salena on the side 

 of the Swiss Yal Ferret. By a single direct barometrical com- 

 parison with Geneva, I obtained 11,284 English feet above 

 the sea, or 140 feet higher than the Col du Geant. I was suc- 

 cessful in traversing the Glacier of Salena to Orsieres the 

 same day, a pass which has not before been described, and 

 which has this interest, in addition to the singular wildness of 

 the scenery, that it includes those regions of beautiful crystal- 

 lized protogine, here in situ, which have been known to geolo- 

 gists hitherto chiefly from the numerous moraines which they 

 form in the valleys of Ferret and of the Rhone, and especially 

 the majority of the blocks of Monthey, which have been 

 derived, according to M. de Buch, entirely from this region of 

 the Alps.* 



* [See a fuller account of this pass in my account of "Norway and its 

 (Glaciers," etc., and also in the "Tour of Mont Blanc," etc., p. 301.] 



