Ege

above its junction with Racing River represents a relatively recent
diversion of the stream from its earlier course ‘northward thr ough the
Muncho Iake-Trout River systom.

Along Muncho Jlake-Trout River vel iey the mountains to the cast -
rise as limestone peaks of considerable height. One of the most prom-
inent, not shown on the map, lies 3 miles east of mile 164 and reaches
an élevation of about ‘7,600 feet. In the valley walls and in small
tributary streams the underlying Cambrian (7?) quartzites and sandstones
are exposed at various places. Along the western side of Muncho lake
the general formational dip is to the southeast ‘and formations underlying
Middle Silurian coral reef formations are exposed about 3 miles north of
the head of the lake. The upper beds are sandstone, but beneath these is
a thick ned: conglomerate that extends northward beyond Muncho Lake to
mile 1973. Within the area of the conglomerate formation are several
high mountains not yet investigated, including one marked on the map as
8,300 feet in elevation.

From mile 1973 to mile 202 the valley is in Siluro-Devonian
limestone. Northward of this point, very soft, black to dark grey or |
brown shale outcrops at intervals into the valley of Liard River, where .
the Rocky Mountain province ends. The northern Rocky Mountains are. flat-
topped or elevated ridges of limestone rising 6,000 feet or more above
sea-level. Their rather abrupt termination at Liord River is probably
due to differential regioml uplift, for the general formational dip is
south, not north as might have been expected. Somé local east-west
faulting has been observed, and this was EnbaR ye & phase of. age differ-
ential uplift.

Liard Valley, dnouk River (Mile iy to Smith River (ile 230)

Uqororerd token: ere crossing of Liard River, near the mouth of
Trout River, the Highway follows the northern bench of the Liard. This
consists. of glacial. silt and river deposits and: supports. an. unusually.
heavy er owth of northern timber. The abandoned gardens, formerly worked
by the ill-fated trapper Tom Smith, are situated at mile 213, and the
hot springs, for which the region is famous, are situated across a beaver
pond a few hundred etine to the northwest. This is, in fact, the so-
called "Tropical Valley". The character of the springs will be discussed
elsewhere in this report. They are in keeping with local evidence of
rock disturbances. Hast of the springs 2 prominent ridge of sandstone ©
and shale rises to an elevation of about 3,200 feet above sea-level. Other,
north-south ridges of shale occur westward to mile 221. No fossils were
found in any of these outcrops, but at mile 213, near the northern footing
of the suspension bridge across Liard River, ‘hard, black, interbedded —
limestone has furnished fossils representative of Mississippian | time. The
shales along this stretch of the Highway are thus correlative with ‘those
of the Banff formation. .

Westward to Smith River (mile 231) the road passes the south
end of limestone ridges that extend for some distance northward. These
rise in places to 3,600 feet and carry reef Cea of Middle Silurian
a2

Black to rusty shale outer ops east of Smith River in a road cut
and similar shale occurs about 1g miles up the river ata 50-foot falls,
where it is downfaulted against grey limestone.

Just west of Smith River a road branches north and continues
25 miles to Smith River emergency landing field. Four miles north of the
forks grey. limestone is exposed in a road cut. Farther north the road
traverses bench lands of gravelly and sandy nature, generally lightly
forested with jack pine and white poplar. The plain has an average
elevation of about 2,200 to 2,300 feet and is typical of the area west

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