74

after moulding, but shrinkage rather high. Burns to pale red, hard body
at 900 degrees C., and dark brown vitrified body at 1,100 degrees C.
Flows smoothly through a die and is suitable for making field drain tile

as well as for bricks. \ Will require admixtures 20 to 30 per cent of sand
because of the high shrinkage. It is not a fire-clay. Outcrops for at least
200 feet along river where.the 5 to 7 feet of overburden could be dumped
into swift current. Flat terrace 120 feet wide with an old. brick-yard,
day mill, and covering racks still: standing.

MINERAL PIGMENTS.

Samples of clay from 17 Mile ranch and from Baker canyon opposite
Quesnel were tested by H. Frechette of the Mines Branch to determine
their values as mineral pigment.

Samples 1 and 2, west of railway cut north of 17 Mile ranch, Fraser
canyon (Figure 2, locality 38).

Sample 1. Red clay from a 10-foot bed of basalt (No. 10, page 12).

Sample 2. Purplish, brown clay from a 30-foot bed of red-brown
andesitic agglomerate (No. 15, page 12). These belong to the Lower
Voleanies (see section on page 12), The beds are only partly turned to
clay.

Samples 1 and 2 when ground in raw oil produce a chocolate brown,
and when burnt and ground in oil a light brown-red colour. The colour
lacked the brilliancy of commercial ochre. The large amount of grit in
these clays makes them of no value in the manufacture of pigments. Clays
from this bank, burnt and mixed with salmon grease, have been used for
generations by the Indians of Pavilion for tracing the tribal history in
pictographs on the rocks. These old drawings retain their colour for a long
time.

Sample 3. From Baker canyon 23 miles from Fraser river, opposite
Quesnel (Figure 1, locality 7, and Figure 12, locality 10). Overlies a bed
of refractory, white clay, No. 6, page 12. ‘It is derived from rocks of the ~
Cache Creek series. There is a thickness of 10 feet of the parent rock
on top of a cliff 80 by 120 feet in horizontal extent, and the clay forms only
‘a part of this. . Three hundred feet north a 3-foot bed of red clay overlies
steel grey clay and conglomerate. This bed has evidently been washed
from the cliff. The clay is not suitable for brickmaking, but may be of
use as a pigment. When ground in raw oil it produces a brown paint
somewhat similar to Peruvian ochre, but not so dark or rich intone. Burnt ©
and ground in oil it produces a brick red paint with the tone of English
Venetian red and lighter in colour than standard Canadian red oxide.
Both raw and calcined materials have good covering and staining power
and would possibly produce a marketable pigment. This material was
used with very satisfactory results in painting a house in Quesnel.

ORIGIN OF THE RESIDUAL CLAYS.

Two possible modes of origin of the residual clays present themselves.
They could have been formed at the surface by weathering of the parent
rocks through the agency of atmospheric waters, or they were formed by
the introduction of the clay substances from the outside; in this case by
means of hot solutions rising from below. The second process seems to
have taken place in this case; the reasons for which are as follows: