1905] WHITFORD—FORESTS OF FLATHEAD VALLEY 197 
are found. The most common companion trees are Populus angusti- 
jolia, Populus tremuloides, and Betula papyrijera. These species 
nearly always form a small per cent. of the spruce forests, and in the 
meso-hydrophytic area along the Flathead River they occupy nearly 
the entire space. In Swan valley the soil is a mixture of clay and 
humus; along Flathead River, especially in the delta region, the 
subsoil is sand, overlaid by a fine alluvial deposit. In the dense 
woods the undergrowth is scanty, sometimes only one or two species 
being present, the most common plant associated with the pure 
spruce growths being Rhamnus alnijolia, although Cornus stolonijera 
is often found. In the narrow strip of this forest along the streams 
nearer the mountain Echinopanax horridum and Veratrum calijor- 
nicum are present. Since the spruce woods are transitional between 
the meadow and the mesophytic woods, the undergrowth of these 
associations is often present. Thus, near the meadow side of the 
forest, grass plots are frequently present, and on hummocks between 
anastomosing channels Lysichiton kamtschatcensis is frequent. On 
the other hand, toward the mesophytic side of the forest the elements 
of the undergrowth of the western larch-Douglas spruce formation 
are to be found. 
An area of spruce is found in connection with a meadow in the 
northwestern corner of the plot not far from the Flathead River. 
Here on the border of the prairie formation is an area that has almost 
identically the same plants as the spruce forest in the Swan valley. 
Along the east side of this swamp there are numerous springs, some 
large enough to give rise to small streams, and others hardly notice- 
able. The source of the water supply is thought to be Echo Lake, 
which, with a number of smaller ones, lies in the depressions of a 
moraine that extends beyond the limits of the plot to the northeast. 
Save a small stream, there is no visible inlet to this lake, and its 
source of water supply is probably by underground seepage from the 
mountains that lie northeast. There is also no outlet above ground, 
and since the drainage is toward the Flathead River it is thought 
that the springs mentioned are fed by underground seepage from 
these lakes and ponds. This underground water level, as shown 
by the wells in the neighborhood, is in places nearly a hundred feet 
below the surface, and extends underneath the larch-Douglas spruce 
