He had chanced to be looking toward the spot from whence the smoke spurt came.
A fallen tree, its top branches hanging down the wall of the defile, provided concealment from which the enemy had sent his shot at Williams.

Sanderson snapped a shot at the point where he had seen the smoke streak, and heard a cry of rage.
A man, his face distorted with pain, stood up behind the fallen tree trunk, the upper part of his body in plain view.
His rage had made him reckless, and he had stood erect the better to aim his rifle at the fissure in which Sanderson was concealed.

He fired--and missed, for Sanderson had ducked at the movement.

Sanderson heard the bullet strike the rock wall above his head, and go ricochetting into the cleft behind him.
He peered out again instantly, to see that the man was lying doubled across the fallen tree trunk, his rifle having dropped, muzzle down, in some bushes below him.
Sanderson heard Williams' voice, raised in savage exultation: "Nip my ear, will you--yon measly son-of-a-gun! I'll show you! "Got him with my pistol!" he yelled to one of the Double A men near him.

"Come on out and fight like men, you miserable whelps!" The young engineer's fighting blood was up--that was plain to Sanderson.