210 ALASKAN MINERAL RESOURCES IN 1906. 
TATLANIKA DRAINAGE. 
About 10 miles east of Totatlanika Creek is the Tatlanika, formed 
by the union of Sheep and Last Chance creeks. This is a somewhat^ 
larger stream and has developed for itself in the section of the valley 
under consideration a gravel plain several hundred feet wide, with a 
grade of about 90 feet to the mile. A finely preserved bench 40 feet 
high and half a mile or more wide limits the stream on the west, and 3 
miles to the west high gravel hills separate the Tatlanika drainage 
from the headwaters of Buzzard Creek ; on the east are blunt termina- 
tions of low, broad ridges that separate the small tributaries entering 
from that side — Grubstake, Koosevelt, and Hearst creeks, on which 
most of the mining is being done. These enter in the downstream 
order given, the mouths being separated by distances of 3 miles and 1 
mile, respectively. The creeks are similar in size and character, and 
gold occurs on all of them under about the same conditions and with 
apparently the same origin. The Tatlanika in this area has not yet 
cut down to hard bed rock and these minor streams have cut narrow 
valleys for themselves in the unconsolidated gravels, clays, and sands 
of the coal-bearing deposits. Grubstake Creek heads along the con- 
tact of the schistose bed rock and the soft deposits and is the only one 
of the three that has the hard bed rock within its drainage basin. 
GRUBSTAKE CREEK. 
Mining on Grubstake Creek is confined to a mile of the lower valley. 
The stream is 200 to 300 feet below the steep inclosing slopes of soft 
material and the stream flat is 150 to 300 feet wide. The grade is- 
approximately 100 feet to the mile. At the lowest stage the creeM 
carries approximately a sluice head of water. The bed rock is sticky 
clay, sand, and coal, all three distinct from the stream deposits. The 
thickness of the gravels that are being mined ranges from a few inches 
to 6 feet. These gravels include both fine and coarse material, with a 
small proportion of bowlders. They are made up oi schist, vitreous 
quart xitc, compact conglomerate composed largely of chert pebbles 
vein quartz, elicit, granite, and diabase; the amount of sediment ii 
them is small. 
Gold is found scattered through about 2 feet of gravel or confinec 
mostly to the surface of the clay bed rock. The pay streak has { 
width of 25 to 7"> feet, hut outside of 25 feet is reported to he patchy 
The coarsest piece found was worth $1.43 and the gold is valued a 
$17.35 an ounce. The common variety is composed of small fla 
pieces, all well worn. Mining is done by open cuts. In some places ; 
few feet of the top gravel are stripped off, hut generally all the mate 
rial from surface to bed rock is shoveled in and the character of grave 
and bed rock is such that 6 cubic yards a day per man can be handled 
