MATANUSKA AND TALKEETNA BASINS. 117 
diey extracted about $4,000. In 1899 A. Gilbert staked Grubstake .. 
jrulcli and in 1900 sold his interest to O. G. Herning, who manages 
;he property for the Klondike Boston Mining Company, of Boston, 
^[ass. 
The valleys of Willow Creek and of the small tributary gulches show 
dearly the results of ice action, the side streams occupying hanging 
valleys, with steep gradients or falls where the smaller streams join 
;he main watercourses. Grubstake Gulch is an example of such con- 
litions. Near its mouth a rim of bed rock crosses the stream and is 
|ut through by the present stream, which falls precipitously about 
L50 feet in a very short distance and enters Willow Creek at a low 
gradient. An excellent dump for hydraulicking is thus afforded. 
The bed rock is a mica schist, penetrated by minute veinlets and 
lugen of quartz. The schistosity at this point is S. (30° W., with a 
steep dip (40°) to the north. The fact that the direction of the schis- 
iosity is across the stream with the dip downstream is especially favor- 
ible for the collection of any gold that might be concentrated from 
he rocks in the process of erosion which the valley has undergone. 
In the last three years, during which time hydraulic methods have 
>een in use, 900 feet of the creek has been worked out. Pay averages 
100 feet in width, witli a depth of 2h to 3 feet. The gold is coarse and 
-ough and at the mint assays $16.58. Very little black sand is found. 
The greater part of the gold occurs close to or in crevices of the bed 
X)ck, but it is not deemed necessary to clean up by hand, the hydraulic 
riant being relied on entirely to sweep all gold into the boxes. The 
vash, which is practically all confined to the gulch bed, there being no 
veil-defined bench, is coarse, ill sorted, and not greatly waterworn. 
Viany large bowlders make it necessary to employ at least two men 
jn breaking up and removing oversize, which adds materially to the 
post of extraction. Three Hendy giants are installed on the property, 
two No. 2 and one No. 1. Only one is used at a time, however. 
*>even hundred inches of water at a pressure of 180 feet is brought 
three-fourths of a mile down the gulch. A 24-inch pipe at the intake 
flam is reduced to 9 inches at the giant, to which is fitted a 3-inch 
nozzle. The 900 feet of sluice boxes used are built entirely of whip- 
Sawed lumber. The bottom boards are H inches thick and the side 
boards 1 mch thick; the frames are 3-inch square timbers. The flume 
is 27 inches wide and 30 inches deep, inside measurements. Block 
riffles are used. A grade of 5 \ inches to 12^ feet is maintained. The 
gravel is piped downstream into the boxes. Very little gold is caught 
ibtV> w the fourth box, the greater part being retained in the second. 
Mercu-y is placed in the third, fourth, and fifth boxes. 
The origin of the gold may be with certainty accorded to the quartz 
stringers abundant in the mica-schists. The coarseness and rough- 
ness of the grains suggest a near source of supply. It is very prob- 
able that the discovery of placer gold in commercial quantities in 
