122 LABRADOR 
all the length of the Labrador; as elsewhere, they may be 
used to determine the directions in which the massive ice- 
cap flowed. Until the year 1900 striz were reported from 
not more than five localities on the coast. In that year 
the list was so far enlarged that it became possible to prove 
a seaward flow for the ice throughout the 750 miles of the 
shore. In Figure 17 arrows have been drawn to show the 
directions of this movement of the ice. 
Besides the scouring and. quarrying, the Labrador ice- 
cap, like all other glaciers, carried out a programme of con- 
structive work. In southern and north-central Canada 
and in the northern United States, this activity furnishes 
for the glacial story a second chapter of even more positive 
importance than the chapter so briefly sketched for the 
Labrador. In northeastern Canada, as we have seen, the 
ice-sheet spent its energies chiefly in transporting to out- 
lying regions the abundant rock-rubbish won from the 
plateau in its polishing and latest sculpturing. That same 
drift was laid down in a broad zone of moraines and water- 
washed deposits of sand, gravel, and clay not far from the 
edge of the ice-cap. The rich farms of southern Ontario, 
southern Michigan, of Illinois, Indiana, Ohio, and other 
northern States of the Union are underlain by the broken 
and pulverized material that once composed the pre- 
Glacial cover of decayed rock in the region to the north 
and northeast. Through the glacial invasion those south- 
ern tracts have gained in the raw material of good soils 
at the expense of northern Michigan and Ontario, of Quebec 
and southeastern Labrador. 
With seemingly greater thoroughness the mantle of soil 
and disintegrated rock has been removed from the coastal 
