GLACIERS 
the ice is moving over a plain, 
behind is not sufficient to push 
Icebergs. — Where glaciers en- 
ter the sea, the tide cuts off frag- 
ments which float away as bergs ; 
or as the glacier moves out into 
deep water, it is buoyed up and 
large pieces are thus cracked off. 
These icebergs (Fig. 122), which 
come abundantly from the great 
Greenland and Antarctic ice 
sheets, are often of immense 
size, being veritable islands of 
ice, which float hundreds and 
even thousands of miles before 
melting. 
Some have been measured 
217 
and the supply from 
it rapidly forward. 
Fig. 121. 
A view in the forest on Malas- 
pina glacier, Alaska. 
Fig. 122. 
An iceberg in Baffin’s Bay. 
whose height above the 
water was five hundred 
feet, and whose length 
and width must be esti- 
mated in thousands of 
feet, while some are re- 
puted as more than a 
mile in diameter. As the 
proportion of ice below 
the water is 8.7 to l 
