Ten thousand landslides take place every spring, contributing their tons of mud to the millions that the river is deporting to the broad catch basins called the Athabaska and Great Slave Lakes.
Many a tree has happened to stand on the very crack that is the upmost limit of the slide and has in consequence 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 overwhelming layer of mud had buried the stumps and grown in time a new spruce forest. Now the mighty erratic river was tearing all this work away again, exposing 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. And the lines of tree trunks to-day, preparing for the next constructive annexation of the lake, are so regular that one's first thought is that this is the work of man. But these are things that my sketches and photographs will show better than words.
When later we got onto the treeless Barrens or Tundra, the process was equally evident, though at this time dormant, and the chief agent was not running water, but the giant Jack Frost.
CHAPTER XXIX
PIKE'S PORTAGE
Part of my plan was to leave a provision cache every hundred miles, with enough food to carry us 200 miles, and thus cover the possibility of considerable loss. I had left supplies at Chipewyan, Smith, and Resolution, but these were settlements; now we were pushing off into the absolute wilderness, where it was unlikely we should see any human beings but ourselves. Now, indeed, we were facing all primitive conditions. Other travellers have made similar plans for food stores, but there are three deadly enemies to a cache—weather, ravens, and wolverines., I was prepared for all three. Water-proof leatheroid cases were to turn the storm, dancing tins and lines will scare the ravens, and each cache tree was made unclimbable to Wolverines by the addition of a necklace of charms in the form of large fish-hooks, all nailed on with points downward. This idea, borrowed from, Tyrrell, has always proved a success; and not one of our caches was touched or injured.
Tyrrell has done much for this region; his name will ever be linked with its geography and history. His map of the portage was a godsend, for now we found that our guide had been here only once, and that when he was a child, with many resultant lapses of memory and doubts about the trail. My only wonder was that he remembered as much as he did.