22 
It was observed on July II and 12, 1930, in a region about 16 miles north- 
west of Indian graveyard, Peace river, and at an elevation of about 2,000 
feet above sea-level. The pine is most abundant on semi-open knolls 
which it shares with black spruce. Lewis, Dowding, and Moss consider that 
the fully matured forest of the lower Cordilleran region of western Alberta 
may consist of Canada and black spruce, and show that the black spruce 
is invading Pinus contorta associations on sandhills in the country between 
Pembina and McLeod rivers (36) . Large areas on the upper slopes of Cari- 
bou mountains are covered with a dense forest of black spruce, mixed with 
a few birches Betula papyrijera var. neoalaskana, and a rather abundant 
growth of alder Alnus crispa. The moss mat is very deep and there is a scat- 
tering of the usual shady woodland herbs : Equisetum sylvaticum var. pau- 
ciramosum, Calypso borealis, Pyrola secunda, Mitella nuda, and Lyco- 
podium annotinum. It is possible that this spruce forest is a more devel- 
oped stage in which Pinus contorta has been crowded out. In several places 
decrepit old pines appeared to be in the last stages of existence, surrounded 
by an almost impenetrable thicket of black spruce. In the more open condi- 
tion mentioned above the ground cover is dominated by a lichen mat Cla- 
donia rangijerina-Cetraria nivalis. The substratum wherever these associa- 
tions were found was of bluish clay without rocks or sand. On the semi- 
open Pinus-Picea hill it was frozen at a depth of about 1 foot at the time 
the notes were made, although it was exposed to the sun during a good part 
of the day. 
In another part of the hills, approximately 5 miles to the southward, 
an outcrop of Cretaceous shale at about the same elevation was found on 
July 23. The bluish clays above mentioned may have been weathered 
shales of this series, a condition that appears the more probable because no 
other such clay soils have been seen to the eastward of the mountain front. 
The thin coating of clay at the top of the outcrop, formed by the recent 
weathering of the shale, bears an open forest of lodgepole pine Pinus con- 
torta var. latifolia, and white birch Betula papyrifera var. neoalaskana , 
mixed with a few Canada spruces Picea glauca . On a small plain along a 
creek at the base of the outcrop is a black spruce muskeg. The entire flora 
in this situation, both on the dry outcrop and at its base, resembles closely 
that on the clay hills described above, and is here sharply contrasted with a 
neighbouring flora on a morainic ridge. On the opposite side of the creek, 
and towering above it, are morainic deposits that reach an altitude of about 
2,300 feet, upon which is a forest of Canada spruce Picea glauca and aspen 
Populus tremuloides . 
It seems probable that certain areas, even if they were crossed by 
glacial ice, received no drift materials, or that if such materials were left 
there they have been removed in post-Glacial time. Should the latter be 
the case, the remnants of the cover, in the form of gravels or coarser mater- 
ials, could be expected in ravines and stream channels, bpt in the first of the 
two areas just described none of these is present. In the vicinity of the 
recognized moraines, corresponding drainage lines contain sand, gravel, and 
a tumble of granite boulders up to several feet in diameter. In the small 
amount of digging done by the writer there was no evidence of stratification 
in the clay soils, nor could any be seen in the bed of a small brook draining 
an upland muskeg on these soils. 
