THE FORMATION OF GLACIERS. 
231 
iar arrangement, and produce a variety o' fea- 
tures most startling and incomprehensible at first 
sight, but more easily understood when studied 
in connection with the whole series of glacial 
phenomena. They are then seen to be the con- 
sequence of the general movement of the glacier, 
and of certain effects which the course of the 
seasons, the action of the sun, the rain, the re- 
flected heat from the sides of the valley, or the 
disintegration of its rocky walls, may produce 
upon the surface of the ice. In the next article 
we shall consider in detail all these phenomena, 
and trace them in their natural connection. Once 
familiar with these facts, it will not be difficult 
correctly to appreciate the movement of the gla- 
cier and the cause of its inequalities. We shall 
see, that, in consequence of the greater or less 
rapidity in the movement of certain portions of 
the mass, its centre progressing faster than its 
sides, and the upper, middle, and lower regions 
of the same glacier advancing at different rates, 
the strata which in the higher ranges of the 
snow-fields were evenly spread over wide ex- 
panses, become bent and folded to such a degree 
that the primitive stratification is nearly obliter- 
ated, while the internal mass of the ice has also 
assumed new features under these new circum- 
stances. There is, indeed, as much difference 
between the newly formed beds of snow in the 
