When they reached the Great Slave Lake they found its islands--notwithstanding their barren appearance--covered with bushes producing a great variety of palatable fruits--cranberries, juniper berries, raspberries, partridge berries, gooseberries, and the "pathogomenan", a fruit like a raspberry.
Slave Lake, however, was still, in mid-June, under the spell of winter, its surface obstructed with drifting ice.

In attempting to cross the lake the frail birch-bark canoes ran a great risk of being crushed between the ice floes.

However, at length, after halting at several islands and leaving Le Roux to go to the trading station he had founded on the shores of Slave Lake, Mackenzie and his two canoes found their way to the river outlet of Slave Lake, that river which was henceforth to be called by his name.

Great mountains approached near to the west of their course.

They appeared to be sprinkled with white stones, called by the natives "spirit stones"-- indeed over a great part of North America the Rocky Mountains were called "the Mountains of Bright Stones"-- yet these brilliant patches were nothing more wonderful than unmelted snow.
A few days later the party encountered Amerindians of the Slave and Dog-rib tribes, who were so aloof from even "Indian" civilization that they did not know the use of tobacco, and were still in the Stone Age as regards their weapons and implements.