CIRCLE PRECINCT. 201 
Farther upstream the creek cuts a greenstone and chert formation, 
! probably of Devonian age, and 10 miles from the Yukon it crosses 
1 1 another belt of Cretaceous slate, which forms the bed rock in Nuo^et 
I Gulch, a small southerly tributary. These rocks are succeeded to 
| the south by a broad belt made up of a Tertiary conglomerate, sand- 
ij stone, and shale series, which contains some lignitic coal seams. This 
ijbelt of coal-bearing rocks has a width of at least 10 miles. Still 
j higher up the valley older rocks are said to occur again. 
Placer gold has been found at two localities in the Washington 
j Creek basin — (1) in Nugget Gulch, about 9 miles from the Yukon, and 
| (2) on Surprise and Eagle creeks, about 10 miles above. The placers 
i on Nugget Creek consist of very much localized accumulations of 
I coarse gold on bed rock. Values are so irregularly distributed that 
it is questionable whether they can be mined at a profit. The gold 
appears to have its source in the Cretaceous slates, and it is worthy 
[ of consideration at least whether the mineralization of the bed rock 
is not sufficiently localized to pay the cost of extraction. The upper 
locality was not visited by the writer, but from the best accounts the 
gold here appears to be derived from a conglomerate. The value of 
the total production of Washington Creek does not exceed a few thou- 
sand dollars. 
COAL. 
Washington Creek has been the scene of some ill-advised attempts 
at coal mining. Though there is considerable lignite in the basin, 
much of the money spent in development has been wasted on experi- 
ments in transportation rather than in testing the seams as to extent 
and quality. The coal openings are from 1 to 14 miles up the creek, 
and as the seams exposed appear to be of no better quality or greater 
thickness than others which lie much closer to the Yukon, the out- 
look for profitable exploitation is not hopeful. The seam examined 
by the writer, about 14 miles from the river, occurs in friable sand- 
stone and shales, striking about east and west and dipping 30° N., 
and showed the following section. The exposure is on the north side 
of the valley, about 40 feet above the stream level. 
Section of coal seam on Washington Creek, 
Roof, soft blue-gray shale. Ft. in. 
Shaly lignitic coal 2 6 
Clay ----- 2 
Shaly lignitic coal 2 
Bone parting 2 
Good lignitic coal ._ 1 
Clay 5 
Good lignite 1 
Clay shale 1 
Impure coal (lignite) - 3 
