The principal diggings at Volcano are in the banks of a gulch, called Soldiers’ Gulch, from its having been first worked by United States’ soldiers, and were of a peculiar nature, differing from any other diggings I had seen, inasmuch as, though they had been worked to a depth of forty or fifty feet from the surface, they had been equally rich from top to bottom, and as yet no bed-rock had been reached. It was seldom such a depth of pay-dirt was found. The gold was usually only found within a few feet of the bottom, but in this case the stiff clay soil may have retained the gold, and prevented its settling down so readily as through sand or gravel. The clay was so stiff that it was with difficulty it could be washed, and lately the miners had taken to boiling it in large boilers, which was found to dissolve it very quickly. To mineralogists I should think that this is the most interesting spot in the mines, from the great variety of curious stones found in large quantities in the diggings. One kind is found, about the size of a man’s head, which when broken appears veined with successive brightly-colored layers round a beautifully-crystallized cavity in the center, the whole being enveloped in a rough outside crust an inch in thickness. The colors are more various and the veins closer together than those of a Scotch pebble, and the stone itself is more flinty and opaque. Quantities of lava were also found here, and masses of limestone rock appeared above the surface of the ground. This place lay north of Moquelumne Hill, and might be called the most southern point of the northern mines. Between the scenery of the northern mines and that of the south there is a very marked difference, both in the exterior formation of the country, and in the kind of trees with which it is wooded. In both the surface of the country is smooth--that is to say, there is an absence of ruggedness of detail--the mountains appear to have been smoothed down by the action of water; but, both north and south, the country as a whole is rough in the extreme, the mountain sides, as well as the table-lands, being covered with swellings, and deeply indented by ravines. An acre of level land is hardly to be found. The difference, however, exists in this, that in the north the mountains themselves, and every little swelling upon them, are of a conical form, while in the south they are all more circular. The mountains spread themselves out in hemispherical projections one beyond another; and in many parts of the country are found groups of eminences of the same form, and as symmetrical as if they had been shaped by artificial means.