While its northern bank was almost destitute of timber, the southern one showed scattered clumps of cottonwood, protected from the devastating prairie fires from the North not only by the river itself, but also by the barren stretch of sand, over which the fires died from starvation. To the right of the caravan lay the grassy, green rolls of the prairie, to an imaginative eye resembling the long swells of some great sea; on the left a ribbon of pale tints, from gleaming whites to light golds which varied with the depths of the water and the height and position of the sun. Massive sand dunes, glittering in the sunlight made a rampart which stretched for miles up and down the river and struck the eye with the actinic power of pure, drifted snow. Here the nature of the prairie changed, losing its rich, luxuriant verdure, for here the short buffalo grass began to dominate to a noticeable extent. The excitement spread. Eager couriers raced back to the plodding caravan to tell the news. Some of the more impressionable forthwith rode toward the river, only a few yards away, hot to be the first to splash in its waters; but they found that prairie air was deceptive and that the journey over the rolling hillocks was a great deal longer than they had thought. But a few miles meant nothing to them and they pushed on, careless of Comanche, Kiowa, or Pawnee Picts, some with their guns empty from the salute they had fired at sight of the stream. The caravan kept stolidly on, following a course roughly paralleling the river and not stopping until evening found it on the far side of Walnut Creek after they had crossed a belt of such poor grass that they had grave doubts about the pasturage at the encampment; and the flinty, uncompromising nature of the ground down the slope of the little divide, in which seemingly for eternity was graven the strands of the mighty trail, seemed to justify their fears. But then, while they were worrying the most, the grass improved and when they had crossed the creek not far from its mouth they found themselves in a little, timber-fringed valley thick with tall grass. And they now had entered one of the great danger spots of the long trail.