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 striae 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 



