They did not seem to be in any immediate danger, for the boat swept along with a free, easy motion that was very pleasant, and the air was delightfully cool after the heat of the sun outside in the open river. But two things worried Dot. One was the fact that she was being carried a long ways from home, and the other a fear of where the underground river might lead them. She wasn't at all sure they were not floating down into the middle of the earth, and the chances of ever seeing Roselawn again were growing smaller every minute. Nothing seemed to worry Tot, however. The darkness and the murmuring of the water made him drowsy, and before long he was fast asleep, with his chubby little arms clasped around Dot's neck. The girl was also gradually recovering from her fright, since nothing terrible seemed to happen. They were having a long journey under the cliffs; but she knew there must come an end to it some time, and probably they would float out of the dark tunnel into the daylight sooner or later. On and on sped the little boat, until at last, as Dot lay staring into the darkness, she noticed a dim light about her, and began to see the rocky roof of the cavern through which they were passing. Then she sat up, and, far away in the distance, she saw a round, bright spot that reminded her of a full moon. It seemed to be getting nearer and bigger, and finally she gave a cry of joy and awakened her companion. "Tot! Oh, Tot!" she called. "We've got to the end at last and are coming out of the tunnel!" Tot sat up and rubbed his eyes. He gave one careless glance at the opening, and then turned his eyes upon the lunch basket, saying, sleepily, "I'm hungry!" CHAPTER 5 THE WATCH-DOG OF MERRYLAND Of course, Dot paid no attention, during this exciting moment, to the boy's demand for food. There would be plenty of time to eat after they were out of the tunnel and in safety. The boat glided on as gracefully as a swan, and in a few minutes it passed through the jagged rocks that formed the mouth of the tunnel and floated into a broad, open river. Dot and Tot quickly scrambled upon the seat and looked around them. They were in a deep valley, shaped very much like a chopping bowl, only around the outer edge were high, peaked mountains. Not a tree nor a green thing was to be seen anywhere, but the valley was thickly covered with stones--big stones and little stones and stones of all sizes--scattered about in every direction. Through the center of the valley ran the broad, blue river, at one end of which was now the boat, while at the other end the children saw a low archway, through which the water seemed to pass into some country beyond. Very slowly the boat was floating toward this archway, and Dot decided there would be ample time to eat something from the basket before they had passed through the valley of stones.