KOUGAROK REGION. 173 
ing placers of the district, little need be said, as (hey are fully de- 
scribed on page 168. Little can be added to the description of the 
second group already given. The terrace gravels merit some closer 
consideration. 
It has already been indicated that the upland region falls off from 
an altitude of about 1,100 feet to the Kuzitrin Valley floor (100 feet 
above sea level) by a gentle slope, here and there broken by a more 
or less well-marked terrace. The best defined of these terraces lies 
about 100 feet above the present water level and is traceable from the 
mouth of Quartz Creek northward along the west side of Kougarok 
River to the point where the valley of the river emerges from the 
upland. A similar feature is found along the northern margin of the 
Kuzijtrin lowland, and the lower part of Turner Creek and some of the 
tributaries of the Noxapaga are reported by Collier to be incised in 
deep gravel deposits, indicating an easterly extension of this same 
feature. Where exposed, the alluvium of which these terraces are 
made up is nearly everywhere seen to be composed of the same charac- 
ter of material — i. e., well-rounded and stratified brown sands and 
gravels. Certain exceptions to this will be noted below. There can 
be no .doubt that these benches are the remnants of an extensive 
gravel sheet. In support of this view are the hillocks made up of 
stratified gravels which here and there stand above the floor of the 
Kuzitrin lowland. 
Near the mouth of Quartz Creek the top of the terrace is about 125 
feet above the water and the gravels rest on clay of unknown thick- 
ness about 15 feet below water level. The exposed material consists 
of well-rounded gravel and sand. On going up Quartz Creek the sur- 
face of the gravel is seen to dip with the grade of the stream, and a 
mile below Dahl Creek about 100 feet of gravel and sand is exposed in 
the valley wall. Above this point this bed was not definitely recog- 
nized, but it is believed to be represented by a white quartz gravel 
that is exposed on Quartz Creek just below the mouth of Dahl Creek. 
On the north side of Dahl Creek valley a shaft sunk to a depth of 180 
feet was entirely in this white gravel and did not reach bed rock. It 
appears probable that these white gravels are a phase of the bench 
gravels of lower Quartz Creek and the Kougarok described above. 
The surface of these white gravels dips to the northwest under the 
trench occupied by Dahl Creek. In other words, the gravels under- 
lying the pay streak at the Lane hydraulic mine and those of Dahl 
Creek are a part of the same bed. The surface of this same gravel 
deposit is believed to be exposed near the mouth of Joe Creek, a tribu- 
tary of Quartz Creek. These relations are too complex to permit 
detailed analysis here, but they point to the following conclusions: 
(1) The auriferous gravels of the Lane hydraulic mine, Dahl Creek, 
and Joe Creek constitute the same horizon; (2) they are underlain by 
