232 
THE FORMATION OF GLACIERS. 
tipper region and the condition of the ice at the 
lower end of a glacier as between a recent deposit 
of coral sand or a mud-bed in an estuary and the 
metamorphic limestone or clay slate twisted and 
broken as they are seen in the very chains of 
mountains from which the glaciers descend. A 
geologist, familiar with all the changes to which 
a bed of rock may be subjected from the time 
it was deposited in horizontal layers up to the 
time when it was raised by Plutonic agencies 
along the sides of a mountain-ridge, bent and dis- 
torted in a thousand directions, broken through 
the thickness of its mass, and traversed by innu- 
merable. fissures which are themselves filled with 
new materials, will best be able to understand 
how the stratification of snow may be modified 
by pressure and displacement so as finally to 
appear like a laminated mass full of cracks and 
crevices, in which the original stratification is 
recognized only by the practical student. I trust 
in my next article I shall be able to explain 
intelligibly to my readers even these extreme 
alterations in the condition of the primitive snow 
of the Alpine summits. 
