It was then supposed that the black cloud, with its muttered thunderings, must be one of those terrible tornadoes which occasionally swept the region, bearing down everything before it.

The men all rushed for the protection of the mustangs.

In the greatest haste they struck off their hobbles and led them into the grove for shelter.
The noise grew louder and louder, and they had scarcely brought the horses beneath the protection of the trees, when they perceived that it was an immense herd of buffaloes, of countless hundreds, dishing along with the speed of the wind, and bellowing and roaring in tones as appalling as if a band of demons were flying and shrieking in terror before some avenging arm.
The herd seemed to fill the horizon.

Their numbers could not be counted.

They were all driven by some common impulse of terror.