Recalled to himself, he looked down mechanically, when his attention was attracted by an unfamiliar object lying in the dust of the trail.

It was a small slipper--so small that at first he thought it must have belonged to some child.

He dismounted and picked it up.

It was worn and shaped to the foot.

It could not have lain there long, for it was not filled nor discolored by the wind-blown dust of the trail, as all other adjacent objects were.