Only at McDame Creek have gold-quartz veins been found close to related gold-
bearing placers. These veins range in width from 1 to 9 feet, are of quartz, carrying
small amounts of pyrite, chalcopyrite, tetrahedrite, and specks of free gold. They are
in sedimentary and volcanic rocks near the eastern margin of the Cassiar batholith
and up-stream from the rich placer section of the creek.

The placer gold on Germansen, Slate, and Manson Creeks is believed to have
originated in carbonatized zones along the Manson fault-zone.

PROSPECTING POSSIBILITIES.

No generalizations of proven value in directing prospecting have been obtained
from the few imperfectly known lode-gold deposits in the Cassiar-Omineca system.
Neither is it possible to point to specific areas having greater known prospecting
possibilities than others. Nevertheless, recent geological work from Manson Creek
northward through the headwaters of the Omineca, Mesilinka, and Ingenika Rivers
has disclosed numerous fault-zones along which mineralization may be localized.

The better known areas,—those that are more accessible and more prospected,
on the basis of known discoveries—have not been overly productive of lode-gold pros-
pects. Two accessible areas lie adjacent to the Omineca River and Manson Creek
Road, and adjacent to Dease Lake and Dease River. These are old placer areas where
hundreds of placer prospectors were active sixty to seventy years ago. No doubt most
outcropping mineral-occurrences have been examined. It will take exceedingly close
prospecting and more advanced prospecting technique to make a new discovery in an
old area. Yet it should be pointed out that only a few parts of the whole area have
been prospected and, of these, very few places have received intensive prospecting.
Much virgin ground awaits the prospector’s attention. Nevertheless, the least pros-
pected areas are also, generally speaking, the least accessible; accordingly, under
present conditions mining costs would be high or might be prohibitive unless very rich
or very large deposits were found.

COUNTRY LYING TO THE EAST OF THE ROCKY MOUNTAIN TRENCH.

GEOLOGY.

The Rocky Mountains consist of an exceedingly thick succession of folded and
faulted sedimentary rocks that range in age from possibly Precambrian to Cretaceous.
The plains to the east are underlain by flat or gently eastward-dipping Cretaceous and
Tertiary sedimentary rocks. With the exception of some basaltic dykes observed by
McConnell on Liard River, between the Turnagain and Rabbit Rivers, and diabase
dykes seen by Williams along the Alaska Highway at Toad River, there are no known
intrusive rocks in the Rocky Mountains north of Yellowhead Pass. The only rocks
that suggest that intrusives might be near-by are the schists mapped by Dolmage
along the east side of Finlay River, between Finlay Forks and Fox River.

EVIDENCE OF MINERALIZATION.

There is very little evidence of ore mineralization in the rocks of the area east of
the Trench. Known occurrences are of small lead-zinc veins just south of Grant Brook,
near Yellowhead Pass, and copper veins east of the Trench about 20 miles north of Fort
Grahame (small copper veins are reported in the area between Akie River and the
head of the Ospika). Copper mineralization is reported to have been found near the
mouth of Gataga River, and an unpublished map showing the explorations of E. B. Hart
in 1913 and 1914 indicates that copper and galena float were found on Toad River, 15
to 20 miles south of Muncho Lake.

Although placer gold has been found on the bars of the Parsnip, Finlay, and Peace
Rivers, no placer gold is known in any of the tributaries draining into them from the

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