KOUGAROK REGION. 167 
fad that Moffit,° in the adjacent region to the northeast, found a 
schist series resting on a massive limestone formation. 
Be 1 lie stratigraphic relations what they may, the fact of the occur- 
rence of two series, one essentially schistose and the other a massive 
limestone, is well established. The limestone occurs in one area 
with oval outline lying between Kougarok and Noxapaga rivers, and 
in another of more irregular contour between Kougarok and American 
rivers. Between these two limestone belts lie the schists, which here 
exhibit great irregularity of dip, being closely folded and faulted. 
Besides the sediments above described, several types of igneous 
rocks occur in this region or immediately adjacent to it. Greenstone 
schists, which are probably altered intrusives, occur with the schis- 
tose rocks. Dioritic rocks, some of them massive, others more or less 
schistose, are not uncommon among the schists as dikes and small 
stocks. A large stock of granite occurs a few miles northeast of the 
Kougarok-Arctic divide. There is a noteworthy hot spring near the 
margin of this granite mass. In the upper Kuzitrin Valley a large 
area is occupied by a basalt lava stream of recent age. 
As in the other placer districts of the peninsula, the schistose rocks 
appear to be the source of the placer gold. Quartz seams and small 
A r eins are common in the schists and many of them are iron stained. 
Reports from prospectors indicate that some of these veins carry gold, 
but, so far as known to the writer, no lodes of commercial value have 
yet been found. It is said that a copper-bearing lode has been found 
in this district. 
There appears to have been two generations of quartz intrusives. 
The earlier of these was injected previous to the extensive deformation 
of the schists, for its veins are crushed and sheared. The later intru- 
sion, which cuts the first system of veins and is comparatively little 
deformed, appears to be more commonly mineralized than the first. 
The presence of the recent granite intrusion at a near-by locality sug- 
gests a genetic relation between the second generation of quartz and 
the granite, but of this there is no proof. 
This district lends additional support to the view elsewhere set 
forth (pp. 25, 130-132), that the locus of mineralization lies at or near 
the contact between the schists and the limestones. There appears 
to be a close correspondence between the limestone and schist con- 
tacts and the distribution of the placer gold, so far as determined. 
The alluvial deposits fall into three groups — (1) stream and river 
gravels; (2) the gravels, sands, and clays which floor the basin low- 
lands; and (3) bench sands and gravels. Glaciation has taken place 
in the Bendeleben Mountains, but there is no evidence that these ice 
masses ever crossed the Kuzitrin Valley to the upland on the north. 
a Moffit. F. II., The Fairhaven gold placers: Bull. U. S. Geol. Survey No. 247, L905. 
