REVIEWS 95 
The outstanding characteristics of each of these three provinces is given 
along with a description of the Mackenzie River, including its lakes and 
larger branches. 
Early pre-Cambrian rocks outcrop in the eastern part of the basin 
and consist of various schists, slates, limestones, and quartzites intruded 
by granites and gneisses. These are overlaid unconformably by sand- 
stones, limestones, and basic flows and intrusives of late pre-Cambrian 
age. The Paleozoic is represented by a series of limestones, shales, and 
sandstones, not subdivided and of unknown age. A series of limestones 
and shales is classed as the Devonian, but the basal part is Upper 
Silurian in age, according to fossil evidence. Beds of gypsum are 
interbedded with these basal limestones, and the strata above the gypsum 
beds are fractured and folded, which is thought to be the result of 
expansion due to the alteration of beds of anhydrite to gypsum. The 
Mesezoic is represented by the Cretaceous sandstones and shales which 
occupy nearly the whole of the valleys of Athabasca and Peace rivers. 
Traced northward from Peace River these formations show three 
changes: a decrease in thickness, replacement of sandstone by shale, 
and a substitution of subaerial for marine conditions of deposition. 
In the sandstones in the basin of Athabasca River there are a number 
of workable seams of coal as well as extensive deposits of bituminous 
sands. A few small areas of Tertiary sands and clays overlie the Cre- 
taceous with slight unconformity. lLignite seams occur in these beds. 
Only the highest parts of the Rocky and Mackenzie mountains 
escaped Pleistocene glaciation. The ice from the Keewatin Glacier, 
which moved north, west, and south, entered this area, as well as ice 
from the mountains to the west. Glacial and lacustrine deposits are 
very extensive. 
Descriptions are given of the bituminuous sands, with a discussion 
of their possible utilization, also notes on the various coal horizons, 
gypsum beds, salt springs, and clays of the area. Cobalt, gold, hematite, 
lead, zinc, and nickel are known to exist but very little is known as to 
their extent. A gas-bearing horizon in the Cretaceous has been known 
for twenty years, also petroleum from borings on the Peace River. 
During the last two years, active prospecting for gas and oil has been 
carried on with favorable results. 
This is a valuable compilation and contribution to the geology 
of this little-known region. In the future it will serve as the starting- 
point for geologists working there. A good bibliography is given. 
To 285 Ae 
