[oe =o 
VICINITY. OF OROVILLE AND CHEROKEE FLAT. 483 
worth from twenty-five cents to a dollar are not uncommon. It is remarkably fine in quality, 
usually ranging between .958 and .968. Gold from the upper gravel alone has been known to 
reach .980. An examination of the returns from the mint for five years shows that in only a very 
few cases has the fineness of this gold fallen below .950, and in a few cases it has exceeded .970. 
It is well known that diamonds have been found with the gold at this point; many of them are 
microscopic, but Mr. Abbey informed me that fifty-six stones had been saved, one of which had a 
value of two hundred and fifty dollars. A sample of the fine goid of this locality has been ex- 
amined microscopically by Mr. Wadsworth. He reports upon it as follows: “The grains are all 
small and flaky, except one, which is of fair size, and shows the abrasion and polish which travel 
only gives. The remainder show but little wear, and were probably all of about the same size in 
the vein-stone. Associated with these are numerous glassy crystals, unworn and generally un- 
broken, which I regard as zircons. Forms identical with them occur in the Sierra granites, and, 
if my memory is not at fault, they are the same as the strange minerals which Professor Zirkel 
regarded as zircons (Micro-Petrography: 40th Parallel Survey). They are abundant in some 
of the gneisses, schists, etc., described by him (Neues Jahrbuch, 1880, 89-92). Magnetite is 
abundant ; besides this, black worn octahedral crystals occur, non-magnetic, which I refer with 
doubt to spinel. Minute, rounded, gray, malleable, magnetic grains were frequently seen (plati- 
num ?). Other minerals of unknown nature exist, but not abundantly ; they are generally in 
angular fragments, and probably belong to feldspar, ete. No transparent mineral was found that 
was isotropic.” 
The water-supply for these mines is drawn from Fall Creek, the North Fork of Feather River, 
Concow Creek, the West Branch of Feather River, and Butte Creek. The supply from these soarces 
amounts to 2,210 miners’ inches the year round, and cannot easily be increased without increasing 
the capacity of the iron pipes in which the water is taken across the deep cations. During the 
rainy season a larger supply is obtained for a few months by storing in reservoirs the water col- 
lected from Table: Mountain. 
The yield of the Spring Valley mines for the first five years after the full supply of water was 
secured, that is, from 1873 to 1878, amounted to $ 2,073,628.69. The cost of operating the mines 
has been about $145,000 per year. In order to secure a proper dumping-ground for the mine 
tailings, the Spring Valley Company has purchased over 19,000 acres of ranch land in the Sacra- 
mento Valley. The lower end of the tailings canal, where it enters the sink of Butte Creek, is 
twenty-five miles from Cherokee Flat. The water then has to make its way for fifteen miles 
farther through the sloughs and the tule swamps, before reaching the Sacramento River. It enters 
the river free from sediment. 
The Spring Valley gravel can be followed in a southeasterly direction as far as the flat at the 
head of Saw Mill Ravine. It then seems to disappear under the basalt, and no other deposits of 
gravel are known to exist from that point on along the northern and eastern side of Table Moun- 
tain, at least not until Monte de Oro, at the southern extremity of the mountain, is reached. 
Oregon Gulch, which lies to the east of Table Mountain, is said to have been extremely rich in 
gold, though it contains no deposits of gravel. It is said also that the ravines leading into this 
gulch from the side of Table Mountain have all yielded richly in gold, while those from the oppo- 
site direction have been nearly always poor or barren. If the enrichment of Oregon Gulch really 
came from Table Mountain, it is somewhat remarkable that the accompanying erosion has left no 
sign in the shape of basaltic boulders on the surface of the ground. To the east of Table Moun- 
tain such boulders are scarcely if ever seen, though they are extremely abundant in the valley to 
the west and southwest of the mountain. 
The deposit at Gregory’s claim, near the base of the basalt on the east side of Monte de Oro, 
is unique. The bed-rock, which is a very rotten slate, has an altitude of 1,033 feet. The so- 
called gravel is at first sight indistinguishable from a clay ; but a little examination reveals frag- 
ments of rough quartz and of some ferruginous variety of rock disseminated through the mass. 
The gold, which is said to be present in paying quantities, is coarse and scraggy. The whole 
