ECONOMIC GEOLOGY. 83 
indifferent creeks and in different parts of the same creek, but make 
up only a small part of the width of most of the valleys. Pay streaks 
ranging* in width from 30 fefct or less to 450 feet, and in one place 
reaching a width of 800 feet, have been reported. The average 
width of gravels carrying values sufficient to pay for working under 
conditions in 1905 is probably about 150 to 200 feet, and this, like 
the thickness, is fairly constant. The pay streaks in the valley floors 
bear no uniform relation to the present stream beds. 
The gold is either evenly distributed throughout the pay gravels 
or lies mostly near the bed rock, or, occasionally, is found chiefly 
within the bed rock. The great bulk of the gold is composed of 
flattish pieces of various sizes up to one-fourth inch in diameter and 
of granular pieces, some of which are mmute. The proportion of 
very fine gold, however, is apparently small, and there is but little 
flaky gold. Nuggets form an inconsiderable part of the clean ups; 
those worth a few dollars are common, however, and a few of con- 
siderable value have been found. Some of the largest were worth 
approximately $145, $160, $190, $233, and $529. Many of the nuggets 
contain quartz. Most of the gold found near the heads of the creeks 
is angular. Downstream there is in general a gradual decrease in 
the average size of the pieces and an increase in the amount of wear 
they have sustained. Nuggets, too, are less common in the lower 
parts of the valleys. In some places coarse and fine gold occur 
together; in others the coarse gold is found mostly on one side of 
the pay streak. At a few localities there appears to be an abrupt 
change from gravels carrying a large percentage of coarse gold to 
others — immediately below on the same stream — Avhose gold content 
is chiefly fine. The values in the pay gravels exploited in 1905 range 
from about 2 cents to 20 cents or more to the pan, and a large part 
of the ground will average about 8 cents to the pan, or about $10 to 
the cubic yard or $2 to the square foot of bed rock. Some of this 
ground averages $3 to $3.50 to the square foot and some carries even 
better values. Assay values were reported ranging from $16.16 to 
$18.25 of gold per ounce, and the gold from one locality was said to 
assay as high as $19.25. 
The minerals most commonly associated with the gold, aside from 
the quartz with which it is often intergrown, are garnet, rutile, and 
black sand. The black sand occurs in but small proportion and is 
composed mostly of magnetite. Cassiterite is rather common, and 
there is some stibnite. Bismuth is occasionally intergrown with the 
gold. 
The frozen gravels are tough, in distinction from the muck. They 
can not be broken with the pick and are with difficulty rent by explo- 
sives. A sudden caving in of the ground undermined in drifting 
24304— Bull. 337—08 3 
