Sanderson could see him, prone, motionless, rigid.
Evidently the two men were doubtful.

Certainly they were cautious.
But at the end of an hour their curiosity must have conquered them, for Sanderson, still alert and watchful, saw a dark blot slowly appear from around the bulging side of a rock.
The blot grew slowly larger, until Sanderson saw that it appeared to be the crown of a hat.

That it was a hat he made certain after a few seconds of intent scrutiny; and that it was a hat without any head in it he was also convinced, for he held his fire.

An instant later the hat was withdrawn.

Then it came out again, and was held there for several seconds.
Sanderson grinned.