“I don’t know,” answered Doctor Dan. “We stayed round here two days after we saw the thing, but it never showed itself again. I’ve got a theory about that, but I don’t suppose you young men care to hear my views.” “Indeed we do,” cried Dick. “Out with it, doctor.” “Why,” replied the Indian, “my idea is that this lake connects with another, which is hidden underground, and that the Plesiosaurus makes its home down there and so gets all the air it needs without coming to the surface at all.” “And a very plausible theory it is,” said Dick. “I was thinking----” Right here Dick was interrupted by a wild cry from Charley. “Look there! Look there!” he shouted, pointing to the rocks right in front of them, which concealed the entrance to another cove. Dick and Dr. Dan grasped their rifles and started back in terror. Right in front of them, not ten feet away, a huge, shiny head, long and flat, with an enormous mouth filled with horrible teeth and two great, glittering eyes set on the sides, projected over the rocks. “The monster!” shouted Dick, and instantly the head darted forward, followed by a long, sinewy neck as big round as a man’s body. The horrid jaws opened and closed with a vicious snap and a frightful bellow rang out among the rocks. CHAPTER IV. CHARLEY IN CLOSE QUARTERS. “Fire!” shouted Charley, and he instantly flung up his rifle and let fly at the huge, snake-like head, which was withdrawn instantly. The bellowing was heard on the other side of the rocks for a moment and then all was still. “What in thunder did you do that for?” Dick burst out. “Don’t you know the orders? On no account were we to kill the creature. By thunder, if you have killed it I am disgraced forever. I wouldn’t have had it happen so for a thousand dollars. How could you be such a fool?” Poor Charley stood abashed. It was a terrible thing to him to be so called down by Dick, but he had allowed his excitement to make him play the fool and he knew it. “Dick, excuse me, please,” was all he said, and then he turned and walked away. Dick was too angry for the moment to follow him or call him back. He had more to say about it and he spat it right out before Doctor Dan. “Softly, softly, sir,” replied the half-breed. “Don’t be too hard on Mr. Charley. He was excited and acted before he had time to think; besides, I don’t think he hit the head or the neck either. Come, we’ll see.” Doctor Dan started to go around the rocks. Dick began to feel a little ashamed of his violence. “Come, Charley,” he shouted. “Come on, old man. Maybe you didn’t hit the Plesiosaurus after all.” But Charley continued to walk in the direction of the camp and never even looked back at Dick. He was a very sensitive fellow and easily offended. Dick knew this and felt a good deal troubled. He wanted to follow Charley up and make it all right with him, but then, on the other hand, he did not like to leave Doctor Dan to face the danger of meeting the Plesiosaurus alone.