Prof. Blake on the Diluvial Deposits in California. 391 
been taken out from claims of the same size. But few of these 
rich spots-have up to the present time been opened, yet there can 
be no doubt but that many still remain to be discovered. Where 
these deposits are found extending over a large surface on the 
elevated flats, gold is always met with, generally diffused through 
the gravel immediately above the rock on which they rest, which 
yields from fifteen to forty cents to the 1U01bs. of dirt. There 
are spots where acres of these deposits have been turned up, in 
which the gravel never contains less than fifteen cents to the 100 
Ibs., and generally more. In the valleys in the lower hills, and” 
even on the plains to the west of them where they are.extended 
over vast tracts of country, these deposits are still auriferous, the 
gold being very generally diffused, and found in greater quanti- 
ties the deeper they are worked. At present they will not pay 
for working, owing to the distance from water, and from the high 
rate of wages. In one place, where water could be readily ob- 
tained, a portion of these deposits situated to the west of the 
lower hills has been worked, and has been found to yield from 
five to thirty cents to 100 Ibs. of earth, through an extent of 150 
acres, the soil being found richer the deeper it is worked. 
The above facts as to the quantity of gold found in these dilu- 
vial deposits are sufficient to prove that they must be the chief 
source from which the gold found in the country has been derived. 
Some undonbtedly has been set free by the gradual disintegration 
of the rocks containing auriferous quartz, but this can afford but 
a small qnantity in comparison with the treasures that must have 
been spread over the bottom of the ocean that existed when the- 
alluvial deposits of the upper hills were formed. And when we 
consider the extreme richness of many parts of those small _por- 
tions of its bed that still remain in situ, and then attempt to form 
an estimate of the treasures that must have formerly existed in it 
when it occupied many thousand times the space that is now 
covered by the deposits that have yielded all the gold already 
taken from the country, we are led to the conclusion that much 
more extensive deposits of gold must exist in California than any 
that have yet been worked. These deposits are undoubtedly to 
be found in the diluvium in the lower valleys and on the plains 
at the foot of the mountains, and will afford a supply of go 
that it will take centuries to exhaust. 
Sacramento, Jan, 15, 1852. 
