Trailin'! by Max Brand

Mile after mile of the rough trail fell behind him, and still the pony shambled along at a loose trot or a swinging canter; the steep upgrades it took at a steady jog and where the slopes pitched sharply down, it wound among the rocks with a faultless sureness of foot.

Certainly the choice of Nash was well made. An Eastern horse of blood over a level course could have covered the same distance in half the time, but it would have broken down after ten miles of that hard trail.