Fair moved forward and dismounted, leaving Diamond in the stream. The sheriff followed.
They stepped lightly across the strip of sand which lay between the water and the willows and Fair turned to the right, circling the clump.
“Here,” he said, “that red steer and the man who drove it went into the wall. I found their tracks that day. They’ve been obliterated by the shifting sand since then.”
He pushed aside a feathery branch and the sheriff at his shoulder craned an incredulous head to look into what seemed the mouth of a cave.
“No—it’s not a cave,” said Fair at his surmise, “it’s a prehistoric underground passage. It leads straight into the heart of Mystery Ridge from this end, and it has an opening somewhere, attested to by this current of wind. This mouth is just wide enough to admit one steer at a time, one horse and rider—but—what more do you want?”
“Great Scott!” cried Selwood again, “of all the impossible things! And not a soul on Nameless knows about it!”
“Wrong!” said Fair, “Kate Cathrew and her riders know. That open plain yonder—it leads out to a town, doesn’t it? On the railroad?”
“Marston—yes. A long way across.”
“Water?” queried Fair.
“Yes—at intervals. Springs. Do for driving—yes—not for range—too far apart.”