198 THE ARCTIC PRAIRIES 



Many a tree has happened to stand on the very crack 

 that is the upmost limit of the slide and has in con- 

 sequence been ripped in two. 



Many an island is wiped out and many a one made 

 in these annual floods. Again and again we saw the 

 evidence of some island, continued long enough to raise 

 a spruce forest, suddenly receive a 

 6-foot contribution from its erratic 

 mother; so the trees were buried to 

 the arm-pits. 



Many times I saw where some 

 frightful jam of ice had planed off 

 all the trees; then a deep over- 

 whelming layer of mud had bur- 

 ied the stumps and grown in time 

 a new spruce forest. Now the 

 A 4j inch birch'spiit by mighty erratic river was tearing all 



^ntntcid 8 ^ this W0rk a W *&> Coring 



all its history. 



In the delta of the Slave, near Fort Resolution, we 

 saw the plan of delta work. Millions of tons of mud 

 poured into the deep translucent lake have filled it for 

 miles, so that it is scarcely deep enough to float a 

 canoe; thousands of huge trees, stolen from the upper 

 forest, are here stranded as wing-dams that check the 

 current and hold more mud. Rushes grow on this and 

 catch more mud. Then the willows bind it more, 

 and the sawing down of the outlet into the Mackenzie 

 results in all this mud being left dry land. 



This is the process that has made all the lowlands 

 at the mouth of Great Slave and Athabaska Rivers. 



