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deposits is about 30 feet high, and extends some 1,500 feet along the river
bank. The tufa is deposited trom the spring waters that emerge from the
calcareous sandstones of the area. It is good material for the manufacture
of quicklime.
STRUCTURAL MATERIALS
LIMESTONE, ETC.

The mountainous areas afford an abundant supply of Triassic and
Paleozoic limestones that might be suitable for building purposes. The
Triassic limestones are nearest to areas of settlement in the Peace River
district. Some of the quartzitic sandstones of the Bullhead group should
make an excellent building stone, and some of the harder beds of the Dun-
vegan sandstone might also be used for that purpose.

M. Y. Williams (1934) has pointed out that raw materials and fuel for
the manufacture of Portland cement are available in close proximity in the
Peace River district. Suitable shale occurs 2 miles up Nabesche (Ottertail)
River; limestone may be obtained 15 miles up Peace River above the mouth
of the Nabesche; and coal is available on Carbon River within a distance
of 12 miles of the Nabesche. On Pine River, a plant situated between the
mouths of Le Moray and Mountain Creeks would have a large selection of
limestone within a radius of 10 miles, shale within 1 mile, and coal on
Pyramid Mountain, within 3 miles.

GRAVEL AND STONE

Plentiful supplies of gravel are available along the river benches and
bars of the larger streams for road building purposes. Where the haul from
stream channels is too great, the Dunvegan sandstones have been quarried
and crusbed for road metal in a few places along the Alaska Highway.
Terminal moraines and eskers furnish large deposits of gravel in a few
localities.

MARL

The occurrence of freshwater marl of excellent quality at Swan Lake
south of Pouce Coupé has been noted by Williams (1934). The deposits
are said to be about a foot thick and to cover the lake bottom where the
water is shallow.

Marls composed mainly of calcium carbonate can be burned locally for
quicklime. They make a valuable land dressing, and are used as an ingred-
ient of cement.

CLAY AND SHALE

The following description of an occurrence of Tertiary pottery clay on

Coal River is taken from William’s 1944 report:

“Fifteen feet ot greyish white clay outcrops below a gravel cover in the
west bank of Coal River, from 14 to 2 miles above the Highway. In all
probability the area underlain is of considerable extent, as each clay outcrop
is about 100 yards in length and the two outcrops are about 200 yards apart.
The Tertiary basin is part of that in which the lignite occurs.