314 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 8, 



has heen employed, for ages, in a way in which thousands of miners 

 now expend their lahour ; that is to say, in separating the gold from 

 the rocky and earthy matrix, and washing away the refuse. Thus, 

 gold may be found in most places over the metamorphic ranges, but 

 more particularly in ravines where frequent land-slips have occurred 

 on the steep sides of hills, and rains have washed the greater part of 

 the earth away, leaving rich deposits of gold behind. According to 

 this view alone (considering the amount of denudation that has taken 

 place), it may be understood why the soil is so rich m gold, while 

 many of the auriferous quartz-veins in the vicinity of rich surface- 

 diggings are comparatively as poor, and it may reasonably be inferred 

 that the superficial debris and clay contain more gold than may be 

 found in the quartz-veins by mining to their utmost depth. See also 

 Carson's Hill {infra), Sonora, &c., pages 312, 316, 318. 



Mormon Creek and other Diggings. — On the north side of Table 

 Mountain there is a stream running parallel with the mountain, and 

 called Mormon's Creek, which has proved rich in some places. At 

 right angles to this, and parallel with the great quartz-vein, runs a 

 deep ravine, bearing the name of the Mormons also. This is about 

 a mile in length, and has been extremely rich. Passing over the hill 

 at the head of this, I came into another ra\dne of equal or greater 

 length and steepness, called Jackass Gulch, trending in the same line 

 vsdth the former, but falling into the Stanislaus in the direction of 

 Carson's Hill. On the other side of the river, another rich ravine 

 (called Indian Gulch) commences and runs nearly to the top of Car- 

 son's Hill. 



Carson's Hill Quartz Mining Works. — After crossing the river, 

 by means of a ferry established at this place, I ascended Carson's 

 Hill, and witnessed the works being carried on there in quartz- 

 mining. The hill is composed of chlorite-slate, rises to the elevation 

 of 500 feet above the level of the river, and is pierced by the quartz- 

 vein already mentioned, which is easily traced down both sides, but 

 projects above the summit like a massive wall. A cross-section of 

 the vein (fig. 4) shows it to be wedge-shaped, being about 20 feet 



Fig. 4. 



-Section of the Quartz-vein in Carson's Hill: from 

 the N. W. Height 200 feet. 



Micaceous slate. 



Chloritic slate. 



Quartz- vein, containing large pieces of slate 

 and auriferous in its upper portion. 



in thickness at the top and decreasing to about one foot at the bottom 

 of the hill. In its thickest part it imbeds large masses of the slate. 



