226 PETROLEUM IN THE NORTH-WEST TERRITORIES. 
locality for petroleum is met with on this river ten miles from its 
junction with the main Athabaska, at which distance, Professor 
Macoun says, ‘‘the men pointed out a tar-spring in the stream, at 
which they very often got tar.” 
He also states that tar oozes from the black shales, 150 feet thick, 
at the forks of these two rivers. Sir John Richardson says these 
shales are underlaid by soft limestone, “‘ which forms the banks of 
Athabaska River for thirty-six miles dowuwards” (from the forks). 
“The beds vary in structure, the concretionary form rather prevail- 
ing, though some layers are more homogeneous and others are stained 
with bitumen.” Limestones, occupying a similar position, re-appear 
on the Peace River near the oil-spring, already referred to, and are 
there described by Professor Macoun as “ almost wholly made up of 
those branching corals ( Alveolites) so common in Devonian rocks, 
intermixed with a species of Zaphrentis in great abundance, some of 
the higher strata being largely made up of these.” When at a part 
of the river about midway between the forks and Athabaska Lake, 
a distance of about one hundred miles, the same gentleman remarks : 
“‘T found below a light grey sandstone, partly saturated with the tar, 
and overlying this, there was at least fifteen feet of it completely 
saturated, and over this again, shale largely charged with alkaline 
matter. This was the sequence all the way, although at times there 
was much more exposed. Where we landed the ooze from the bank 
*had flowed down the slope into the water and formed a tarred sur- 
face extending along the beach over one hundred yards, and as hard 
as iron ; but in bright sunshine the surface is quite soft, and the men 
when tracking “along shore often sink into it up to their ankles.” 
Sir John Richardson says: ‘About thirty miles below the Clear- 
water River the limestone-beds are covered by a bituminous deposit 
upwards of one hundred feet thick, whose lower member is a con- 
glomerate having an earthy basis much stained with iron and colored 
by bitumen. * * Some of. the beds above this (conglomerate) 
stone are nearly plastic from the quantity of mineral-pitch they con- 
tain. Roots of living trees and herbaceous plants push themselves 
deep into beds highly impregnated with bitumen; and the forest 
where that mineral is most abundant does not suffer in its growth. 
* * Further down the river still, or about three miles down the 
Red River (of the Athabaska), where there was once a trading 
establishment, now remembered as ‘La Vieux Fort de la Riviere 
