pkindle.] BIRCH CREEK REGION. 65 
Eagle ('reek has a length of about 4 miles. The valley widens 
rapidly below the junction of the forks until the valley floor becomes 
one-fourth mile or more in width, bounded by spurs, which recede 
gradually as the mouth is approached and terminate in broad low 
slopes at Birch Creek. Work has been done for about 2 miles below 
the junction. The bed rock and gravels are similar to those on the 
other creeks; the depth to bed rock at the localities visited varied 
from 14 to IS feet; about 6 feet is ground sluiced, and pay is found 
in about (> feet. Values have been found ranging from $125 to about 
$400 per box length of 12 by 18 feet, Some of the gold is coarse, one 
piece worth $74 having been found. Work was being done at only a 
few places on the creek; on one claim a drain was being put in pre- 
paratory to winter drifting; at another locality the ground was 
worked by open cuts, but the depth to bed rock made it necessary to 
shovel the dirt first to a staging and then to the sluice boxes. The 
grade of the gold of Eagle Creek and Mastodon Fork is the best 
found in the Birch Creek region. About 20 men were working on 
these creeks in September, 1903. 
SUMMARY. 
The conditions of occurrence on all of the gold-producing creeks of 
the Birch Creek region are apparently the same, Xo foreign wash 
was anywhere observed, and there is no reason to believe that the gold 
has had other than a local origin. The quartzite-schists contain 
numerous small quartz stringers, and pieces containing gold in the 
niartz seams have been found. It seems probable that here is at least 
Dne source of the gold. The bed rock, so far as known, is about the 
>ame over a large area. Only a feAv of the streams within this area 
ire gold producers. In a broad way, then, the occurrence of gold 
shows localization. Whether the rocks have been uniformly miner - 
dized over a considerable portion of the drainage basin of a stream or 
)nly within certain zones or areas along its course which are relatively 
*ich is a problem that can be solved only by detailed study. When 
>old has originated from local rich areas it can often be traced to its 
source. 
The process of distribution, or decentration, as it might be called, 
3f the gold from such local areas through the agency of gravity and 
oca! wash precedes that of concentration, and its results may be often 
)bscured or removed by the stream action which brings about the 
later concentration. It seems probable, in view of what facts we 
possess, that the gold found on the creeks of the Birch Creek region 
las been derived from large areas of bed rock more or less uniformly 
nineralized; that there are probably no zones or pockets especially 
-ich in the metal: and that the distributed products from the areas 
Bull. 251—05 m 5 
