

SAN JUAN TO NORTH BLOOMFIELD. 



395 



much larger percentage of slate and other metamorphic rock. This lower gravel is for the most 

 part a hard cement, excepting for a width of about 200 feet in the deepest part of the channel, 

 where there is a stratum on the bed-rock which is soft and easily worked. On the rim the hard 

 cement extends to the bed-rock. The best paying gravel is found within ten or fifteen feet of the 



bottom. 



Lar^e boulders are not common. 



There was no one at work at the time of my visit. 



For a distance of nearly half a mile farther to the south from the high bank just referred to, 

 the top gravel, particularly on the west side of the deposit, has been removed pretty extensively. 

 The general surface of the gravel also rises in this direction towards the Flat to the north of the 

 town of Cherokee. Considerable prospecting has been done on the Flat, but no great depth has 



been reached at any one place. 



To the south of Cherokee there has been no mining to speak of. Some shallow gravel is found 

 along the crest of Pleasant Ridge, which is very likely an overflow from Columbia Hill. 



Between Cherokee and Columbia Hill, south of the stage road, and near the junction of the two 

 forks of Shady Creek, a great deal of work has been done in the Chimney Hill mines, but the 

 creek is now choked with debris, and there was nothing doing when I was there. The Chimney 

 Hill prospect shaft I did not visit. It is said to have been sunk to a depth of between 150 and 

 160 feet, and to have reached blue gravel, though work was suspended before reaching bed-rock, 



on account of the influx of water. 



At Columbia Hill extensive mining lias been carried on at the Laird claims, at the Farrell 

 claims on the southern side of the deposit, and at the Consolidated mines on the right bank of 

 Spring Creek. At the time of my visit the principal work was doing at the Farrell claim. The 

 banks at this claim extend to the southern rim -rock, and vary very much in height 



Flie gravel 



exposed to view was of a decidedly reddish color for a thickness of ten or twelve feet from the 

 surface, but lower down it was much lighter, almost white, in color. The mass of the material 

 was fine and sandy or clayey, with no regular and persistent strata of pipe-clay. The pebbles were 

 small in size and mainly quartz, or of some variety of quartzose rock. Some of the clayey layers 

 presented peculiarities of structure or color, which may be noticed. One layer, whitish in color, or 

 yellowish white, was consolidated almost to the consistency of rock, and showed a well-marked 

 slaty cleavage. Other layers were of a dark blackish-blue color, resembling some soft bituminous 

 shales, and showing a cleavage structure. At one part of the claim, covering an area of thirty or 

 forty acres, a dark-colored pipe-clay, six or eight feet in thickness, rests directly upon the bed-rock, 

 with no gold in it or under it. I did not examine this locality with any especial care; it may be 

 that the clay has resulted from a local disintegration of the bed-rock, instances of which are very 

 common in other parts of the State. The gravel here is very easy to move, and very little use is 

 made of powder or pick, except to break up the larger blocks of clay which the water, unaided, 



would not move through the sluices. 



I did not make any close examination of the gravel at the Consolidated mines. It is very fine, 

 sandy, and easily worked. The outlet is through Spring Creek. A pressure of 270 feet can 

 be obtained in these mines, while in the Farrell and the Laird the pressures are 100 and 120 

 feet respectively. On the Consolidated ground two eight-inch nozzles will deliver 2,500 inches 

 of water while on account of the difference of pressure, the same sized nozzles in use at the other 

 claims use much less water. Nozzles as large as ten inches in diameter have been used, but only 

 exceptionally. Eight inches is the ordinary size. 



At Grizzly Hill the gravel has been removed for a few hundred feet back from the edge of the 

 canon, and the estimated height of the bank at the upper end of the workings is 125 feet. The 

 lower fifty feet is blue in color, and the top, as usual, is red. No large boulders were seen here. 

 The gold is said to be scaly. The property now belongs to the North Hloomlield Company. 



Between Columbia Hill and Lake City there are some extensive surface openings, where the 

 top gravel has been removed. Rut the tunnels were all too high, and the mines are for the present 



abandoned. 



At Malakoff about fifteen acres of deep bed-rock have been exposed, along a line of 1,700 feet 















