BY CAPTAIN P. W. HUTTON. 441 



than they do, which cannot be the case in so slow a movement as 

 glacier flow. Nothing but lateral pressure squeezing the ice out 

 all round the stones is, I think, capable of explaining their 

 parallelism. 



The origin of the larger system is not so obvious. As the clear 

 ice bands of both systems blend when they meet it is not possible 

 to make out by mere inspection which is the older of the two. If 

 the coarser system is the older, I think I should have noticed it 

 higher up the glacier, which I did not do. If, on the other hand, 

 the coarser system is the newer, it is difficult to see why the rock 

 fragments are not parallel to it. Possibly it may have some other 

 origin than pressure. 



Mr. Guyot says that on the Gries glacier, in Switzerland, the 

 surface is "covered with regular furrows, from one to two inches 

 Avide, hollowed out in a half snowy mass, and separated by 

 protruding plates of harder and more transparent ice."* Professor 

 J. D. Forbes makes a somewhat similar statement. He says 

 "These bands or veins were conspicuously distinguished (on the 

 glacier of the Aar and others) by two characters — (1) Difference 

 of hardness, (2) Difierence of colour. The former distinction 

 causes the harder (which are also the bluer) veins to stand up in 

 ridges, as the ice melts by the action of the sun or rain, and 

 allows the comminuted sand from the moraines to lodge in the 

 intervening linear hollows, which led, as we have seen, some 

 persons to suppose that the heat of the sun, acting upon the sand, 

 caused the hollows in which it lay. This peculiarity is admirably 

 seen on many parts of the Mer de Glace ; and nowhere better 

 than upon tlie common route from the Montanvert to the Jardin, 

 where it passes by the foot of the Aiguille des Charmoz, between 

 the Aiigle and Trelaporte. Here the whole surface seems striated 

 with fine lines ; and where groups of the harder bands occur, there 

 are projecting ridges, with grooves between, continuous for very 

 many fathoms along the ice, resembling the cart ruts of a much 



• Quoted by Tyndall in Formn of Water, p. 184. 



