He ran, and she could not stop him, pull hard as she might.

If he had only run towards home! But instead, he ran down the valley, because then he need not face the wind; and he tried to outstrip the wind as he went.
It was when they topped a low knoll and darted under the wide, writhing branches of a live oak, that Jack glimpsed them and gave chase; and his heart forgot to beat until he saw them in the open beyond, and knew that she had not been swept from the saddle by a low branch.

He leaned lower over Surry's neck and felt gratefully the instant response of the horse; he had thought that Surry was running his best on such uneven ground; but even a horse may call up an unsuspected reserve of speed or endurance, if his whole heart is given to the service of his master; there was a perceptible quickening and a lengthening of stride, and Jack knew then that Surry could do no more and keep his feet.

Indeed, if he held that pace for long without stumbling, he would prove himself a more remarkable horse than even Dade declared him to be.
He hoped to overtake the girl soon, for in the glimpses he got of her now and then, as she flew across an open space, he saw that she was putting her whole weight upon the reins; and that should make a sufficient handicap to the gray to wipe out the three-hundred-yard distance between them.

It did not seem possible that Tejon could be running as fast as Surry; and yet, after a half-mile or so of that killing pace, Jack could not see that he was gaining much.