As it was he was compelled to watch them all.
But presently, at the edge of one of the two larger rocks, the one nearest the slope, he detected movement.

A round object a foot in diameter, came slowly into view from behind the rock, propelled by an unseen force.

It was shoved out about three quarters of its width, so that it overlapped the big rock beside it, leaving an aperture between the two of perhaps three or four inches.

While Calumet watched a rifle barrel was stuck into this aperture.

Calumet waited until the muzzle of the rifle became steady and then he took quick aim at the spot and pulled the trigger of his six-shooter, ducking his head below the edge of the gully as his weapon crashed.
He heard a laugh, mocking, discordant, followed by a voice--Taggart's voice.
"Clean miss," it said.