38°00 RESOURCES OF CALIFORNIA. 
Bar, and Pine Log. The first four are within a circle with a 
radius of five miles, a district which has been extremely rich 
in placer diggings, and especially in large nuggets. In 1850 
two lumps of twenty-three pounds, one each of eighteen, thir- 
teen, ten, five, four, and three pounds, were found; in 1851 
one each of twenty-eight, twenty-four, twenty-three, and five 
pounds; in 1852 one each of nine and five pounds; in 1853 
one each of twenty, ten, nine, eight, seven, and six pounds; in 
1854 one each of seventy-two, twenty-seven, sixteen, and seven- 
teen pounds; in 1855 one of thirty pounds; and in 1858 one 
of thirty-three pounds. Two of the largest mining ditches in 
the state supply water to the miners in the vicinity of Sonora 
and Columbia. The number of mining ditches in the county 
is twenty-one, and their aggregate length two hundred and 
seventy miles. There are thirty quartz-mills, of which four are 
at Quartz Hill, four at Tuttletown, three on the banks of the 
Tuolumne River, and as many on Turnback Creek, at Colum- 
bia, Soulsby’s Ranch, and Wood’s Creek two each, and at Bald 
mountain, Big Oak Flat, Italian Camp, Jackson Flat, Moc- 
casin Creek, Rawhide Ranch, Sonora, Whiskey Hill, Wood’s 
Crossing, and Yankee Hill, one each. The table-mountain in 
Tuolumne county is the most remarkable elevation of its kind 
in the state. It has an average height of five hundred feet, an 
average width of four hundred yards, a length of thirty miles, 
and a surface almost perfectly flat, slightly descending toward 
the west. It was evidently formed by an immense stream of 
lava, which was once confined between banks higher than its 
own surface, which banks have since been washed away, leay- 
ing the stream of lava standing like a mountain above the level 
of the adjacent country. The sides near the top are perpen- 
dicular and of solid basalt ; farther down they are sloping, and 
composed of dirt and fragments of basalt that have fallen from 
above. Under the basalt lie the gravel and sand of the ancient 
river-bed, enclosed at the sides by ridges of rock, which rise 
above the level of the adjacent plain. When therefore the min- 
ers first wished to reach the auriferous deposits under the moun- 
