The Lost Herd: A Novella — Joseph Altsheler

A green valley is discovered by two men.

Steep cliffs isolate the valley, but the men decide to investigate. They descend the cliffs through what appears to be the only path to the valley.

At the bottom they begin an exploration and discover a herd of buffalo. It is a mystery as to how the buffalo could have gotten there.

The men are eager to kill some of the buffalo. But strange things happen here, and the men would have been better served to stay out of this valley.