His Indian guide informed him that rocks of a similar kind were scattered about the country at the back of the Slave Lake, near where the Chipewayans collected copper.

If so, there may be a great oilfield yet to be discovered in Arctic Canada.
On the river coming out of the Bear Lake Mackenzie discovered coal; the whole beach was strewn with it.

He was attracted towards it by seeing smoke and noticing a strong sulphurous smell.

The whole bank of the river was on fire for a considerable distance, and he thought this was due to the natives having camped there and set fire to the coal in the bank from their hearths.

But subsequent travellers have also found this lignite coal burning to waste, and imagine that, being full of gas, it catches fire spontaneously if any landslip or other accident exposes it to moist air.