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1905] WHITFORD—FORESTS OF FLATHEAD VALLEY 215 
of these depressions comes near enough to the water level to permit 
the growth of scattered Engelmann spruce. This level of under- 
ground water varies, and this change is shown in the rise of the lake 
itself and the ponds around it (fig. 15). 
Mention has already been made of the western larch-Douglas 
spruce combinations on the protected slopes of the Mission Moun- 
16.—View on the top of the Mission Mountains showing area on which the 
Douglas spruce-bull pine forest has been destroyed by fire; the outcrop of dolomitic 
Shale has been scoured smooth by the action of glacial ice; Ceanothus bushes on the 
right, lichens of various sorts on the rocks, and prairie grasses where the soil is suffi- 
ciently deep.—From photograph by PRAEGER. . 
tains. Toward the top of this slope western larch becomes less and 
Douglas spruce more prominent; in places the latter is mixed with 
lodgepole pine. On the west side of the range Douglas spruce and 
bull pine are the principal species; hence this area has been mapped 
4S Meso-xerophytic, although western larch is present in some 
situations. 
