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Tertiary Dyko Rocks

Qn the north and west slopes of Taltapin Mountain, and
close to the areas of Tertiary lavas near the cast end of Babine
Lake, andesitic and basaltic dykes rolated to the Tertiary lavas
are abundant. They are dark green, fine-grained, hard rocks
commonly impregnated with pyrite. |

Conglomerate

A poorly consolidated conglomerate has been found in two
localities. Five miles west of Mott Williams it is exposed over
an area = square mile in extent, and 2 miles south of the west end
of Trembleur lake an exposure 100 yards square is found, In both
cases the exposures unconformably overlie Tertiary lavas.

The conglomerate is made up of pebbles and boulders
ranging in size from = inch to 2 feet in diameter. The pebbles
and boulders are fairly well rounded and consist mainly of
amygdaloidal and vesicular andesite, granite, greenstone, serpentine,
and chert. The matrix, which is very crumbly, is siliceous, The
thickness of this conglomerate is unknown, but it does not exceed
200 feet.

Calcareous Tufa

Along the north shore of Trembleur Lake calcareous tufa
has been deposited by springs along fissures in the argillites.
Individual deposits are from 3 to 6 inches thick, and 10 to 25
square feet in area, The tufa is a white to buff, porous rock
composed of calcite and fragments of argillite around which the
calcite has been deposited.

ECONOMIC GHOLOGY

Only a limited amount of prospecting has been done in
the map-area north of Babine Lake, and until recently mineral claims
had been developed only south of this lake, The proportics near
Babine Lake are: the Taltapin group, the Radio Gold Mince, Limitod,
ana the Silver Island Mining Company. As theso properties were
described in detail in the report™ on the arca south of Babine Lako,

ort Fraser liap-Area,
Gb. OF inos and

"Preliminary Report on the West Half of the
B.C., Paper 37-13, 1957; Geol, Surv. D
Resources, ppe 17 and 19 to 23,

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