And when Sanderson discovered that Dale's horse was failing, he urged Streak to a faster pace.

In an hour the space between the two riders had become less.

They were climbing the long, gradual slope that led upward out of the basin when Dale's horse stumbled and fell, throwing Dale out of the saddle.
There was something horribly final in the manner of Dale's falling, for he tumbled heavily and lay perfectly quiet afterward.

His horse, after rising, stumbled on a few steps and fell again.
Sanderson, fully alive to the danger of haste, rode slowly toward the fallen man.

He was taking no chances, for Dale might be shamming in an effort to shoot Sanderson as he came forward.
But Dale was not shamming.