870 
barrows, then wheeled and dumped through 
chutes in the floor, and hauled out of the tun- 
nels in cars. 
Along certain narrow streaks the ore was of 
good grade, carrying values as high as several 
hundred dollars to the ton ; but it has been the 
policy of the company to work the deposit on a 
large scale and in a cheap manner; hence, 
everything has been removed which contained 
sufficient gold to pay a small profit. In this 
way the average yield per ton of the ore was, 
during the first few years, brought down to $7 
and even $5 in gold and later this was further 
decreased to $3.50. From month to month 
the ore showed a remarkable uniformity in 
tenor, although but 40 to 70 tons were handled 
per day, and this was taken haphazard within 
the limits of what was determined to be the 
ore-body. 
Running through the center of the deposit, 
and parallel with its major axis, there was a 
narrow dike of white acid porphyry, such as is 
commonly associated with gold-bearing veins 
of this region, and the entire ore-body has fre- 
quently been reported as a mineralized dike. 
However, the acid dike is not ore, but is thrown 
away as waste. On both sides the ore-body 
extended away from it to a distance of 20 to 50 
feet and terminated irregularly in the mass of 
the decomposed rock, there being no well- 
marked walls or other evidences of common 
vein action. The grade of the ore was closely 
connected with the intensity of the iron stain 
and particularly with the quantity of brown 
manganese oxide present. 
At first thought, this large deposit of red, 
soft, decomposed rock carrying free gold was 
considered the upper or oxidized portion of a 
zone of impregnation of auriferous sulphides 
such as are rather common in this northwestern 
California region ; but a consultation with the 
superintendent of the mine, Mr. F. N. Fletcher, 
brought to light some facts which demonstrate | 
that it is certainly of an entirely different char- 
acter. It is unique among deposits of this 
country in the following two points: 
1. It is absolutely free from any traces of 
pyrites changed to limonite such as are always 
found in panning the surface portion of other 
veins. 
SCIENCE. 
[N.8. Vou. XIII No. 335. 
2. It does not present any evidence of pass- 
ing in depth into a shear zone modified by 
solfataric action and impregnated with aurifer- 
ous sulphides. 
Upon first arrival at the mine, the writer 
was impressed by the marked resemblance in 
the tint and character of the deep red staining 
to those of certain accumulations of residual 
red clay found frequently in hollows in the 
surface of limestone formations, as, for in- 
stance, over the Galena limestone in the Mis- 
sissippi basin. This suggested an explanation 
for the origin of the deposit which was subse- 
quently worked out as follows: 
The site of the King Solomon mine, which is 
at present the top of a mountain ridge, was 
once the bottom of a rather deep, broad basin 
eroded by subaerial agencies from a series of 
quartzites, black slates and limestone. This 
series was intersected by numerous narrow 
branching dikes of greenstone. Evidence that 
a small amount (say a trace) of gold was a pri- 
mary constituent of this system of eruptives 
has been found in different parts of this country. 
The carbonated meteoric waters circulating 
laterally and downward beneath the slopes of 
the basin, dissolved gold out of these green- 
stone dikes and carried it, along with iron and 
manganese salts (derived from pyrites in the 
quartzites and slates), to the center of the basin, 
where, just beneath the surface, these minerals 
were precipitated as free gold, ferrous carbonate 
or hydrous ferric oxide and some salt of man- 
ganese, perhaps the last inits present form of 
oxide. Precipitation was probably due, as in 
the case of limonite and wad in bogs, to the de- 
creased circulation of the water at the center of 
the basin, and in part also to the water rising 
close to the surface and becoming subjected to 
the oxidizing influence of the atmosphere. 
Subsequently, through great erosion of the 
region, the water level was depressed in the 
strata, the basin no longer existed, and the 
limonitie deposit worked downward, penetrat- 
ing to unequal depths in different places. The 
porous schists and slaty rocks were deeply 
stained with the oxide and impregnated with 
gold, but the acid dike in the center of the de- 
posit was largely impervious to the solution 
and escaped heavy mineralization. 
