So they swept on through the darkness over the empty waste, the trooper who was riding hard slowly creeping up behind.  Still, Winston held the horse in until a glance over his shoulder showed him that there was less than a hundred yards between them, and he fancied he heard a portentous rattle as well as the thud of hoofs.  It was not unlike that made by a carbine flung across the saddle.  This suggested unpleasant possibilities, and he slackened his grip on the bridle.  Then a breathless shout rang out, “Pull up or I’ll fire.”

Winston wondered if the threat was genuine or what is termed “bluff” in that country, but, as he had decided objections to being shot in the back to please Courthorne, sent his heels home.  The horse shot forward beneath him, and, though no carbine flashed, the next backward glance showed him that the distance between him and the pursuer was drawing out, while when he stared ahead again the dark shape of willows or birches cut the sky-line.  As they came back to him the drumming of hoofs swelled into a staccato roar, while presently the trail grew steep, and dark boughs swayed above him.  In another few minutes something smooth and level flung back a blink of light, and the timbers of a wooden bridge rattled under his passage.  Then he was racing upwards through the gloom of wind-dwarfed birches on the opposite side listening for the rattle behind him on the bridge, and after a struggle with the horse pulled him up smoking when he did not hear it.

There was a beat of hoofs across the river, but it was slower than when he had last heard it and grew momentarily less audible, and Winston laughed as he watched the steam of the horse and his own breath rise in a thin white cloud.

“The trooper has given it up, and now for Montana,” he said.

CHAPTER IV

IN THE BLUFF

It was very dark amid the birches where Trooper Shannon sat motionless in his saddle gazing down into the denser blackness of the river hollow.  The stream ran deep below the level of the prairie, as the rivers of that country usually do, and the trees which there alone found shelter from the winds straggled, gnarled and stunted, up either side of the steep declivity.  Close behind the trooper a sinuous trail seamed by ruts and the print of hoofs stretched away across the empty prairie.  It forked on the outskirts of the bluff, and one arm dipped steeply to the river where, because the stream ran slow just there and the bottom was firm, a horseman might cross when the water was low, and heavy sledges make the passage on the ice in winter time.  The other arm twisted in and out among the birches towards the bridge, but that detour increased the distance to any one traveling north or south by two leagues or so.