GLACIERS. 675 



is evinced in the successive transverse crevasses of a cascade-glacier 

 like that of the Khone, or in the dirt-bands which are registers of 

 the successive crevassing. Each movement, moreover, must cause 

 a series of vibrations, of great force, in the ice. Such intermittent 

 and oscillatory action is especially calculated to produce a laminated 

 structure. As Tyndall has observed, the air-cells appear to have 

 been in part expelled from the bluish layers by the pressure, and in 

 part to have been obliterated by an incipient liquefaction and re- 

 freezing of the layer. 



In the lower part of the glacier of the Ehone, the laminated 

 structure is produced, according to Tyndall, between the capes m 

 and n (fig. 951), — the structure-mill, in his language. It appears first in 

 the section s, and is fully developed in the following one, s / . The 

 radiating lines in the view represent crevasses. 



This lamination is very distinct over parts of most glaciers. It 

 is well shown either side of the middle of the Mer de Glace ; it 

 gives a longitudinal structure to the central portions of the Aar 

 Glacier below the junction of its two great branches, the Finster-Aar 

 and the Lauter-Aar ; it characterizes, according to Forbes, the whole 

 of the Brenva Grlacier. 



2. Transportation and erosion. 



1. Transportation. — The moraines of glaciers are made from (1) the 

 stones and earth which fall from the cliffs along their borders ; 

 (2) the material received from falling avalanches ; (3) that which 

 is taken up by the ice from the surface of the valley against which 

 they move. They form in all the stages of progress of a glacier, 

 though usually the least in the region of the neve, where the peaks 

 are often small compared with the extent of snow. The surface in 

 this upper part is always peculiarly white and clean, owing to the 

 frequent falls of snow. 



From their mode of origin, it follows that moraines are situated 

 primarily along the margin of a glacier. But, when two glaciers 

 coalesce, the two uniting sides join their moraines in one ; and this 

 one is remote from the borders, and may be central — as in the glacier 

 of the Aar — if the two coalescing streams are about equal. It fol- 

 lows from the above that the number of moraines on a glacier can 

 never exceed the number of coalesced glaciers by more than one. 



In ,the Grlacier of Zermatt, the nearest moraine in the view (fig. 

 953) is that of the Kiffelhorn ; the second is a union of moraines of 

 the Gornerhorn and Porte Blanche ; the third, a union of two mo- 

 raines from two Mt. Rosa Glaciers ; the fourth, the great moraine of 

 the Breithorn, the summit in the middle of the view. Other 



