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.