"You mean, Jim, that you think we had better go on and have a chaperon, just as we planned, as though there was no danger of our losing the ranch?" Jim nodded silently. He placed a cautious finger on his lips. He was leaning forward in his saddle, intent on something ahead. Jack did not notice. "We don't want to have any one to live with us whom we know nothing about," she went on, "so I expect we had better send for mother's cousin, Ruth Drew. She is a fussy New England old maid, and terribly prim, but she wrote she would come out to us, and if she can stand for us, why,--what was that, Jim?" Jack finished breathlessly. "Shsh!" Jim whispered softly. "Keep perfectly still until we know." CHAPTER XII. ON THE OTHER SIDE OF THE DIVIDE. JIM COLTER and Jack had ridden to the lower end of Rainbow Creek, where it widened into a kind of natural reservoir. Some yards beyond it, a line of upright rails divided the Ralston ranch from that of the Nortons. The earth dipped slightly on the farther side and a thicket of low sage brush covered the rise in the land beyond. Jim and Jack saw nothing moving in the sage brush or beyond it and there was no one in sight. Their impression must have been a mistake, for the only living thing in view was a flock of wild geese which flew over their heads uttering their shrill clamor. Jim sat erect, silent and watchful as an Indian, on the back of his equally motionless pony, his hand shading his eyes. Jack waited on her horse gazing at the quiet waters of Rainbow Creek. Suddenly there came a low rumble inside the earth, like a note of warning, and then the land began to rise in sandy billows as though wave on wave were seeking some distant shore. The two horses with their silent riders shook as with the ague; the face of Rainbow Lake shivered, then her waters lashed the shores as though they had been parted asunder, and a moment later receded and began to disappear. It was as if old Father Neptune had deserted his home at the bottom of the sea to play his mighty games in the shallow waters of Rainbow Creek. It seemed as though he had blown a great blast through his sacred horn and caused the water to spurt upward, then had drawn it slowly back into his horn again. The noise and the movement died away. "Was it an earthquake, Jim?" Jacqueline managed to murmur, as soon as she could get her breath. She had slipped quietly off her pony and was patting it softly, for the broncho was terribly frightened at the strangeness of his experience. Jim nodded solemnly. "A human earthquake, I guess. Don't be alarmed, it won't occur again, but get to cover quickly."