They knew not thai man's mentality had begun to grow, and would continue until the world was swept free of the cumbersome, useless creatures of Pliocene, and their old trails would be no more.

These trails are buried now, under the drill of glaciers and the wash and ashes of the ages. And the trails of glaciers, the ice-grind

of centuries are strewn with stranger rocks and stones, torn from the breast of their mother mountains, and carried on long journeys, and each peculiar kind, and its worn face, tells the story of its pilgrimage.

The glaciers melting, poured released floods in natural channels, and new rivers began the first hilarious journey to the sea. Possibly the same liquids have made the same journey many times -- coming back in vapors and falling in rain or snow -- and then following the water trails made by the melting glaciers, centuries ago.

Deer, buffalo and elk, kindred and hostile beasts of early America, made the trails of the later "Overland." They crossed the gaps in the Pineridge, and in the Scotts Bluff- Wildcat range; they meandered up and down the valleys, and made worn thoroughfares over the South Pass, long before the American Indian found the heart of the new world.

We can go back only a relatively short period in our stories of events along the old trails, for only the smooth surfaces of stones, only silent fossils of giant things, only echoes from a disintegrating atmosphere, and the dumb silent zodiac, furnish the meagre information as to what happened here, before the halfsavage French or Spanish trapper and adventurer penetrated the vast wilderness of the new continent.