The gravel of the ancient Stanislas river being very auriferous, great efforts have been made to reach the portion of it which lies under Table Mountain. Large sums have been spent in sinking shafts from the top through the lava cap, and tunnelling into it from the sides. Great masses of gravel have been thus quarried and removed, and a considerable amount of gold obtained, though in most cases not enough to meet the expenses, and the workings have been mostly discontinued. [Illustration: SECTION ACROSS TABLE MOUNTAIN, TUOLUMNE COUNTY, CALIFORNIA. _b_, lava; _G_, gravel; _S_, slate; _R_, old river-bed; _R´_, present river-bed. (Le Conte.)] It is evident that objects brought from a great depth below this lava cap must have remained there undisturbed since they were deposited along with the gravels, and that the evidence of the simplest miner, who says he brought them with a truck-load of dirt from the bottoms of shafts, or ends of tunnels pierced for hundreds of feet through the solid lava, is, if he speaks the truth, as good as if a scientist had found them _in situ_. And this evidence, together with that of mining inspectors and respectable residents who took an interest in scientific subjects, has been forthcoming in such a large number of instances as to preclude any supposition of mistake or fraud. Three of the latest of these discoveries were reported at the meeting of the Geological Society of America on the 30th December, 1890, and they seem to be supported by very first-class evidence.[14] Mr. Becker, one of the staff of the United States Geological Survey, to whom has been, committed the responsible work of reporting upon the gold-bearing gravels of California, exhibited to the Society a stone mortar, and some arrow or spear-heads, with the sworn statement from Mr. Neale, a well-known mining superintendent, that he took them with his own hands from undisturbed gravel in a mine of which he had charge under the lava of Table Mountain. [14] Professor Wright in _Century_, April 1891.