It has been urged with considerable force that these relics have been left behind by ancient miners when they mined for gold. Dr. Wilson is cited as authority for the statement that the Mexicans obtained “silver, lead, and tin from the mines of Tasco and copper was wrought in the mountains of Zacotollan by means of galleries and shafts, opened with persevering toil where the metallic veins were imbedded in the solid rock.” Prescott, the historian, also testifies to the same fact. We need only add to this, that wherever these ancient galleries were opened in the solid rock, they still exist. Schoolcraft mentions finding one two hundred and ten feet deep.17 The chances are not worth considering, that these old mines would be overlooked. If, for instance, the Calaveras skull is that of a prehistoric miner, killed in an old mining gallery only a thousand years or so ago, it is inconceivable that all evidence of this mine should have disappeared. Or, if in one case it should have done so, it would surely have been detected in other instances. The variety and explicitness of the testimony brought forward makes all such supposition improbable.18 It is best, in this matter, to hold the judgment in suspense. We have stated Mr. Whitney’s position, and the objections that have been raised to it. The amount of thought bestowed on the antiquity of man will doubtless soon clear up the whole matter. We can not do better than to consider his surroundings, supposing that he was really present. The country must have been very different from the California of to-day. Dr. Cooper says, “The country consisted of peninsulas and islands, like those of the present East Indies; resembling them also in climate and productions.”19 The probabilities are that to the west and southwest of California, instead of watery expanse of the Pacific, only broken here and there by an ever-verdant islet, there was either a continental expanse of land or, at any rate, a vast archipelago. We know that over a large part of the Northern Pacific area the land has sunk not less than six thousand feet since late Tertiary times.20