190 ALASKAN MINERAL RESOURCES IN 1906. 
carrying pyrite and galena, and it is reported to carry values of $6 
in gold and $8 in silver. 
Spurr a reported the finding of gold-bearing quartz on Harrison 
Creek. He describes the occurrence as follows: 
The best example of gold-bearing quartz found in the gravel is a rhomboidal block 
of quartz schist, about 4J by 5 by 2 inches, found on claim 91, on North Fork, about 
three-quarters of a mile above the forks. On one of the larger surfaces of this block 
is a quartz vein which is richly spotted with flakes and specks of gold, ranging from 
three-sixteenths of an inch in diameter to mere specks, which finally become invisible 
to the naked eye. 
These facts indicate that the placer gold is derived from zones of 
mineralization in the schist series. The wide distribution of the 
placer gold is not a favorable indication that the values are suffi- 
ciently localized in the bed rock to afford commercial ore bodies. 
It must be said, however, that there is little evidence on this point, 
and workable lodes may yet be found when a systematic search is 
made. 
The alluvium, like the bed rock, varies in character. Nowhere 
was any foreign material observed in the stream gravels, and as a 
rule there is a progressive increase in size of material toward the; 
headwaters of any given watercourse. Where mining operations 
have been carried on the extreme depths to bed rock usually do not 
exceed 20 to 30 feet and probably do not average more than 8 feet. 
In most sections the material becomes very angular toward bed rock. 3 
The bed rock itself is in general deeply weathered, and the material 
excavated usually includes 2 or 3 feet of it. Along nearly all the 1 
creeks one or more benches occur on the valley slopes. Those that 
have been found to carry values are from 2 to 20 feet above the! 
present stream floors. The character of the alluvium on the benches 
is similar to thai of the valley bottoms, but much of it is deeply 
buried under talus, or "slide rock,'' as the miners call it. This talus 
has in many places so obscured the original topography that the 
benches are not found until they are developed by mining excava- 
tions. At several localities the writer observed still higher benches, 
40 to 50 feet above the present stream floors, but these appear to be 
very local, and even if found to be auriferous are beyond the reach 
of the present water supply. 
A feature repeatedly observed in this province by Prindle is the.] 
asymmetrical character of the valleys when viewed in cross section. 
One wall is usually steep, with benches entirely absent, while the 
other has a gentle gradient and is broken by numerous benches. 
The miners have taken cognizance of this fact in their prospecting, 
which has been devoted chiefly to the gentle slopes where the old 
channels and benches, if present, would be preserved. 
a Spurr, J. E., Geology of the Yukon gold district, Alaska: Eighteenth Ann. Rept. U. S. Geol. 
Survey, pt. 3, 1898, pp. 353-354. 
