Accordingly, when Professor Whitney states as the result of many years spent in the investigation of the Tertiary formation of California, that he finds evidence of the existence of man in the Pliocene Age, it is not strange that one part of the scientific world listens incredulously to his statements, and are at once ready to explain away the facts on which he relies. He may, of course, be mistaken, for it is human to err, but his proofs are sufficiently strong to convince some of the best scholars in America. We can do no more than to lay the facts before the reader and let him judge for himself. We have seen what a genial climate prevailed in Europe during the Tertiary Age. This must also have been true of California. A rich and varied vegetation decked the land. The great trees of California of our day then flourished in Greenland, Iceland, and Western Europe. The cypress of the Southern States was then growing in Alaska and other high northern latitudes. The climate probably passed from a tropical one, in early Tertiary times, to a milder or temperate one in Pliocene times. Amongst the animals inhabiting America were three species of camels. Rhinoceroses, mastodons, and elephants trooped over the land. Tigers and other carnivore prowled in the forests. Herds of horse-like animals, one scarcely distinguishable from our common horse, grazed in the valleys, along with several species of deer. From the presence of the old drainage beds, we know that majestic rivers rolled their watery burden through the land. Such a country might well afford a home for man if he were present. To understand fully the course of events which now took place we must venture on geological ground. The great Pacific Ocean, lying to the west of America, is constantly exerting a lateral pressure, which during Tertiary times showed its effect in the uplifting of the great mountain ranges of the western coast.2 During late Tertiary times, as a counterpart to the upward movement, a great subsidence commenced in the Pacific region.3 Doubtless many islands, some think an entire continent even, disappeared beneath the waves. The completion of the various mountain ranges left the coast firm and unyielding; hence, as it could not bend before the fiery flood forced upward from below by the downward motion just mentioned, it broke, and the torrent of molten rock leaped out as a lava flow. In consequence of this, near the close of Pliocene times, the surface of California and Oregon, especially the north of California, became buried under the lava and ashes of the most desolating volcanic outbreak that the earth has ever known.