The Chinese Parrot by Earl Derr Biggers

If Bob Eden had known the identity of the passenger in the taxi that he and Holley passed on their way to the mine, it is possible that, despite his concern for Paula Wendell, he would have turned back to Madden's ranch. But he drove on unknowing; nor did the passenger, though he stared with interest at the passing flivver, recognize Eden. The car from the Eldorado station went on its appointed way, and finally drew up before the ranch house.

The driver alighted and was fumbling with the gate, when his fare leaped to the ground.