GLACIERS 37 
snowfields. The mountains of Britain were under 
perpetual snow. From the mountain-snows glaciers 
were formed, and they found their way down valleys 
and on to the plains, carrying with them fragments 
of rock, even boulders of many tons in weight, as 
well as earth and stones. The under surfaces of 
the glaciers were rough with stone fragments, which 
rubbed against the rocks over which they were 
ins 
ae Foye 
eps, Pe Wes oe 
Fig. 5.—Forratep Rocks, Locu Fyne. 
Dark wavy layers are shales metamorphosed into schists, and the 
white bands are much altered sandstone. 
forced, making grooves and scratches by a grinding 
action. When the glaciers reached the plains they 
melted, and dropped the fragments they had carried. 
These fragments are often found in heaps, and as 
scattered boulders. 
A little thought will make it clear to you that 
fragments torn away from mountains, carried several 
miles by glaciers, and dropped in some valley or 
