GLOLOGY. 53 
and from six to eight times heavier than the clay and stones 
with which it is found, has sunk to the bottom of the diluvium. 
The best diggings are therefore near the “bed-rock.” The 
dirt in which the gold is found is usually a stiff day, with 
gravel and large stones intermixed. The common phrase 
“golden sands” may mislead. Pure, fine sand rarely has any 
gold in it; and the richest deposits of the precious metal are 
in a clay so tough as to give the miner much trouble to dis- 
solve it, with stones in it weighing from a pound to several 
hundred weight. The character of the pay-dirt varies greatly. 
A hill of diluvium may be three hundred feet deep, with a 
dozen strata of different material, and all of them auriferous in 
different degrees. In some places the pay-dirt is full of boul- 
ders, weighing several hundred pounds or more; in-other 
places the stones are all about as large as a man’s head; in 
others, as large as a hen’s egg. In one stratum the dirt is 
red, in another blue, in another brown. In some places the 
dirt was deposited in basins of rock, four or five miles across, 
and from ten to fifty feet deeper at the centre than at the rim. 
The placer-diggings are all found in a very rough, mountain- 
ous country. The gold has not been carried far; its weight 
has anchored it near its mother-vein. There may be much 
gold in the Sacramento valley ;:but if so, it is deposited be- 
neath one thousand feet of diluvium, and nine hundred feet 
below the level of the sea, where it-will never be disturbed. 
The déluvial placers are in-what are called hill and flat dig- 
gings; the alluvial, made by streams running through the 
diluvium, are in river-beds, bars, ravines, and gullies. The 
alluvial placers, as a general rule, are richer than the diluvial. 
The streams have carried away much of the dirt, and left 
nearly all the metal. Most of the gold of the rivers comes 
from gullies. There is a gully on a mountain: it is dry, ex- 
cept during heavy rains; it has steep sides. The rain comes ; 
the water pours down its sides, fiercely sweeping clay, gravel, 
and gold along. The bed of the ravine is not so steep as the 
sides ; most of the gold stops there; the dirt is carried away 
