PLACERS OF THE RAMPART REGION. 69 
York, California, and many other creeks of the region whose valleys 
lie in parallel or nearly parallel directions. 
The rocks in the upper part of the valley are mostly closely folded 
slates and. limestones. Garnetiferous schists occur at Ruby Creek, 
and greenstones form the bed rock of the lower valley except near the 
mouth, where they are partly covered by the Kenai rocks. 
The alluvials of the valley are said to be 10 to 12 feet thick and 
consist of the usual muck (soil mixed with much vegetal matter), 
peaty soil, and gravel, with much angular debris at the foot of many 
of the hillsides. In the middle part of the valley they consist of 
about 5 to 6 feet of muck and the same thickness of gravel. The 
muck thickens toward the sides while the bed rock remains about 
level. The gravel deposits are derived from local bed rock and con- 
tain large numbers of smoothly rounded quartzite bowlders from a 
few inches to 3 feet in diameter, whose source has been a mystery to 
many. Some of these bowlders have undoubtedly descended to the 
present creek bed from the high benches already referred to, in whose 
gravels they are abundant. 
The outcrop of quartzite near the " 72 road house " would in itself 
seem sufficient explanation for the bowlders below, but above this 
point the thinner quartzite beds have added many more to the stream. 
The quartzites are so hard and their abrasion is so slow that while 
the other rocks wear into sand and small pebbles, or decompose and 
are swept away, the quartzite bowlders remain and make up a con- 
tinually larger proportion of the gravels. 
Mining. — Minook Creek has not produced a large amount of gold. 
The wide valley, large stream, and heavy gravels have made mining 
difficult, so that men with the limited means of the ordinary pros- 
pector have found it more advantageous to work the smaller streams. 
The total production to 1904 is placed by miners of the region at 
$9,900. The gold produced is said to have been taken from the cen- 
tral portion of the valley, partly from bar diggings and partly by 
drifting, but in general the gravels do not seem to be rich enough for 
working by pick and shovel methods. 
Nothing was learned of the ocurrence of gold in the gravels of 
Minook Creek above the mouth of Slate Creek, except that colors 
have been found throughout its length. Below the mouth of Ruby 
Creek colors of gold are said to have been found in the gravels of a 
bench on the west side of Minook Creek, a few feet above the present 
stream, but not in paying quantity. The debris here is largely a 
carbonaceous slate someAvhat schistose and highly impregnated with 
pyrites. An assay a of some of the material gave a trace of silver. 
Two small areas worked in the gravels between Ruby ami Slate 
Creeks are said to have given values of about $3 per square yard of 
a Burlingarne, E. E., & Co., Denver, Colo. 
