For half an hour he lay still and watched them.

Then one of the Nannies struck out with her two kids for the side of the mountain; another followed, and seeing that the whole band was about to move, Langdon rose quickly to his feet and ran as fast as he could toward them.
For a moment Nannies, Billies, and little kids were paralyzed by his sudden appearance.

They faced half about and stood as if without the power of flight until he had covered half the distance between t hem.

Then their wits seemed to return all at once, and they broke in a wild panic for the side of the nearest mountain.

Their hoofs soon began to clatter on boulder and shale, and for another half-hour Langdon heard the hollow booming of the rocks loosened by their feet high up among the crags and peaks.