MESOZOIC AND CENOZOIC GEOGRAPHY 485 
varieties of these deposits. However, the subject should not be 
left without stating the main reasons for the conclusion that the 
ice sheet really did come, and how the facts stated above prove 
it. There is a belt, extending up hill and down, and stretching 
across the country in a general east and west direction, north of 
which the country presents entirely different conditions from 
those to the south. North of this area, which is that of the ter- 
minal moraine, there is an abundance of lakes, gorges, and water- 
falls, while south of it they are uncommon. 
Also, the soil is not due to rock decay, as it is to the south, 
but is made of clay, mixed 
with bowlders and pebbles, 
whose home and origin is 
north of their present posi- 
tion, and sometimes hun- 
dreds of miles to the north. 
Something has _ carried 
these, and of all the agen- 
cies known, ice is the only 
one that is capable of trans- 
seg “epee — Fic. 268. 
reat distances an e- 
8 mas Glacial striz on rock over which glacier has 
positing them surrounded an 
by beds of clay. More- 
over, the bowlders show signs of grinding, for the clay in which 
they are bedded is a true rock flour, and the pebbles are scratched 
and smoothed (Fig. 113). The bed rock over which the materials 
have been carried is also polished, grooved, and striated by the 
scouring it has received (Fig. 268). These striz point toward 
the direction from which the bowlders have been brought. 
Long before the glacial theory was proposed to account for 
these peculiarities, it was thought that the surface of the land 
had been covered by immense floods of water, which had deluged 
even the highest mountains, and strewn the surface with the 
glacial and other deposits. It was believed that these floods had 
