He hoped that Cliff was afraid of being lost, and of landing on some high mountain that stuck up like a little hill above the general assembly of dimpled valleys and spiny ridges and hills.

But if Cliff were afraid he did not say so, and when the double-pointed hill that Johnny had reason to remember slid toward them, Cliff pointed ahead to another, turned his head and shouted.
"See that deep notch in the ridge away off there?
Fly toward that notch." Johnny flew.

The double-pointed hill drifted behind them, other hills slid up until the two could gaze down upon their highest peaks.
Beyond, as Cliff's maps had told him, lay Mexico.

At eight thousand feet he shut off the motor and glided for the notched ridge.

The patrol who sighted the Thunder Bird at that height, with no motor hum to call his attention upward, must have sharp eyes and a habit of sky-gazing.