kiNDLE.] FAIRBANKS REGION. 75 
ptal depth to bed rock so far as determined by prospect holes is over 
b feet. 
1 Pedro Crccl,\ — The depth to hod rock has been found to vary from 
to 30 feet, and the deposits show generally the threefold division 
ito muck, barren gravels, and pay dirt. The muck varies in thick- 
ess from a few inches to over 20 feet, is made up of decomposed vege- 
ible matter with a considerable proportion of sand and clay, and is 
tatted together and interlaced with roots. Interbedded with it are 
ccasional thin lenticular beds of sand and fine "chicken \\>r<\ " 
ravel. The gravels underlying the muck vary from 1 to 20 feel in 
hickness, but the average thickness in most localities is about 10 
eet. They are composed chiefly of quartzite-schist and mica-schist. 
tith some granite, gneiss, and vein quartz. The pieces are rather 
ngular, mostly under a foot in diameter, and there are few bowlders, 
luch fine material of the same nature is mixed with the coarser frag- 
ments and generally the gravels near bed rock are characterized by 
he presence of a yellow, sticky, micaceous clay, containing minute 
ragmen ts of schist and quartz. The lower gravels are thus often 
ather sharply demarcated from those above them, and the fact that 
he occurrence of gold is limited to this portion of the gravels has led 
o their designation as the " pa}^ dirt." The arrangement of the 
■ravels, although often irregular, is due essentially to stream action. 
The gravels containing the gold vary in thickness from 1 to 4 feet, 
nd gold is also found in the bed rock to a depth of from 1 to 5 feet, 
me width over which the ground has been found to contain sufficient 
'old for working varies from 40 to over 200 feet, and in several cases 
s over 100 feet. The values of the pay dirt vary up to 2^> cents to 
he pan, and much of the ground which has been worked has probably 
iveraged about $1.50 to the square foot of bed rock. 
The gold occurs generally as small, flat pieces. No large nuggets 
lave been found, but several were seen ranging in value from $6 to 
14; a $19 piece is perhaps the largest that has yet been found. 
31ack sand, garnets, rutile, and iron pyrites are the most common 
issociates. 
In the summer of 1902 gold was discovered on Pedro Creek, about 
me-half mile below the mouth of Twin Creek, at a depth of about 
L4 feet in sufficient quantity to yield 20 cents to the pan. The work 
)f prospecting spread rapidly up and down the creek and along 
he tributaries. In the fall of 1903 claims were being worked on 
rwin Creek, on Pedro Creek from Twin Creek to Gilmore Creek, and 
>elow on Gold Stream. In 1904 developments were confined mostly to 
lie main creek between Twin and Gilmore creeks, a distance of about 
> miles. No further work has been done on Twin Creek except near 
he mouth. Some work has been done on Gold Stream, but no exten- 
sive development has yet been undertaken. 
