542 W. L. UGLOW AND W. A. JOHNSTON.

STATEMENT OF THE PROBLEM.

The question of the source of the placer gold in the Cariboo
district, British Columbia, has been one of interest to mining men
and prospectors almost since the discovery of the placers. The
fabulous richness of the placers in certain restricted parts of sev-
eral of the creeks—2™% miles of Williams creek and its tributaries,
for example, being credited with a production of about 19 millions
of dollars °—and the coarseness and angularity of much of the
gold were strong indications that the placer gold was of decidedly
local origin. After the exhaustion of the richer portions of the
gravels in the 70’s, the attention of prospectors was directed
towards a search for the mother lode. The only occurrence of
auriferous lodes in the region is a belt of quartz veins which
crosses the drainage basins of the creeks; and deposits located in
this belt were prospected by means of tunnels and shallow shafts.
Free gold was found only in the upper, disintegrated and decom-
posed parts of the veins, but not in quantities that seemed large
enough nor of the proper character, to be the source of supply of
the gold for the rich placers.

The problem of the origin of the placer gold, therefore, should
be solved by the answers to the following questions:

(1) Was the placer gold derived from these auriferous quartz
veins?

(2) Are the quartz veins, as at present exposed, merely the
roots of deposits whose upper eroded portions contained much
greater quantities of primary free gold?

(3) If not, and assuming that the upper eroded parts of the
veins contained minerals similar to those of the parts now exposed,
is there any evidence to show that the placer gold might have been
derived from the veins?

(4) If the evidence points in the direction just indicated, what
combination of processes could explain the derivation of the placer
gold from the veins?

(5) Does the geological and physiographical history of the
region show that conditions were favorable for such a derivation?

2 Ann. Rept. Minister of Mines, B. C., 1896.