Danny Dunn and the Fossil Cave Read online

  “Tut, tut, my dear man,” the Professor began.

  Mrs. Dunn interrupted him. “Just a moment. Nobody’s asked me what I think.”

  “Oh, Mom!” Danny cried. “Please say we can go. Please!”

  “Hmmm. I don’t know.”

  “I really don’t think there will be any danger,” said the Professor. “In the first place, both Alvin and I have had considerable experience in speleology.”

  “It’s not your spelling I’m worried about,” Mrs. Dunn said.

  “Speleology is the scientific study of caves,” Professor Bullfinch smiled. “Both of us have done a good deal of caving, and we’ll take all the necessary precautions. In the second place, I feel that Danny deserves this trip. You may not realize it, but this morning he did something that showed great strength of character. You heard what Irene said: he was about to explore the cave, but then he saw to it that Tresselt got here, instead. I don’t think Dr. Tresselt would have given up an interesting project like that. I’m not even sure I’d have done so myself.”

  “It’s a good thing he didn’t mention it this morning,” Dr. Tresselt said, with a chuckle. “I probably would have camped on the spot.”

  “That’s what I mean,” Mrs. Dunn said, drily. “I’m not too worried about Danny. He knows how to take care of himself, and I’m sure I can trust him to be cautious. It’s you two grownups I’m worried about.”

  “Us?” The Professor looked blank.

  “Just so. You’re liable to get these youngsters into that cave and then start one of your investigations and forget all about them. They might manage to get home—but will you?”

  The Professor and Dr. Tresselt looked at each other and then at Mrs. Dunn. They both had rather foolish expressions, like overgrown schoolboys being scolded by the teacher.

  Irene put in, “Oh, Mrs. Dunn, we’ll promise to take care of them and see to it that they don’t get into trouble.”

  Mrs. Dunn’s eyes twinkled, and she got up and began to clear the table. “Well,” she said, “I’ll give my permission for Danny to go, in that case.”

  “I’m going home right now,” said Irene, jumping up, “and ask my mother, but if you say it’s all right, she will too.”

  “Okay,” Danny said, picking up a pile of dishes to take to the kitchen. “Then come back. You too, Joe. We’ve got lots of plans to make and things to get ready for tomorrow. The Bullfinch-Tresselt Underground Expedition is on its way!”

  CHAPTER SIX

  Slide into Darkness

  Although the night was damp and cloudy, the morning dawned bright and clear and the expedition hiked up through the woods under a brilliant sky. As Danny remarked, it wouldn’t make much difference to them what kind of day it was once they got underground, but it raised their spirits immensely before they started.

  They found the way without difficulty, following Irene’s blazed trail. As they approached the big oak tree, Dr. Tresselt stopped and pointed to a deep gully cut in the earth like a wagon road.

  “Many of these caves in limestone hills were carved out by flowing streams,” he said. “That gully shows where the stream may once have come out.”

  “And there’s the cave itself,” Danny cried, in excitement.

  They could see that the oak tree stood on a rocky point formed by two great slabs leaning against each other. Below was a black opening, like the entrance to a teepee. They climbed up to it, and then paused to pull on sweaters or heavy jackets.

  They were all variously loaded down. Dr. Tresselt carried a powerful battery lamp belonging to the Professor; Professor Bullfinch had another such lamp and his C-ray; the three young people each wore a knapsack and carried a good flashlight. Irene had a first-aid kit in her pack, and spare batteries for all the different lamps. Joe’s knapsack was stuffed with sandwiches, chocolate bars, and cookies. Danny opened his pack and took out a square metal box with a handle at the top, a pair of earphones, and what looked like a microphone on a cable attached to it.

  “Well, well,” said Dr. Tresselt. “A Geiger-Müller counter, eh? Planning to do a little prospecting for uranium?”

  “I doubt there’s any around here, Danny,” said the Professor, gravely.

  “It’s not for that at all,” Danny replied, checking over the instrument and replacing it in his pack. “But since this is a scientific expedition, we ought to do the whole thing scientifically. So this is for finding our way back.”

  “I don’t think I quite understand,” the Professor said. “How is a Geiger counter going to help?”

  “Well, I borrowed this from Professor Blum, in the Physics Department, yesterday,” Danny said. “And I also got from him some thorium nitrate crystals. They’re mildly radioactive, you know, and they’ll register on the counter and make it click rapidly. I’ve got ’em in this little box. Every time we come to a place where there’s more than one way to go, I’ll drop a few of them. Then, when we come back, we can pick up our trail with the counter. See?”

  The Professor rubbed his bald head. “I see. But wouldn’t it have been easier if you had just brought along a small can of white paint and a brush?”

  “Easier?” Danny shook his head, scornfully. “Gosh, no! Opening and closing a can of sloppy paint? And messing around with a brush?”

  “As it happens, I brought along a piece of chalk,” Dr. Tresselt observed, mildly.

  “Chalk? But gosh, Dr. Tresselt,” Danny wailed, “that isn’t scientific at all!”

  “All right,” said Professor Bullfinch. “We’ll let you do it your way, Dan, since you’ve made such careful preparations. Now, are we all set?”

  “Right!” said Dr. Tresselt.

  “I’m ready,” said Joe. He took a notebook and a pencil out of his pocket. “Ten A.M. The expedition arrived at the cave entrance and prepared to make its way to the very center of the earth.”

  “Sounds exciting,” said the Professor. “Only I don’t think we’ll be going that far down.”

  “It’s what they call ‘artistic license,’” Joe explained. “I’ve decided to write a report about the trip for the school magazine, and I have to make it seem dangerous even if it isn’t.” He gulped nervously. “Anyway, I sure hope it isn’t.”

  “I’m ready,” said Irene. She jingled the charm bracelet, which this morning she was wearing on her wrist. “I’m going to see if I can find something interesting to represent geology on my bracelet.”

  “Let’s go, then,” said the Professor.

  He stepped forward, snapping on his lamp. Danny was right at his heels, and the others pressed close behind.

  They stood in a rock chamber with high, arching walls. Under the beams of their lights the wall shone like glass, and here and there clusters of white crystals flashed out. The floor was covered with loose stone and gravel. The ceiling, arched and craggy, sloped down toward the back of the cave where it was lost in darkness.

  Dr. Tresselt bent and picked up what looked like a round, white pebble. “Carbonate of lime,” he said. “The result of the passage of water through the limestone.”

  Irene and Joe drew close to look. Danny, after a glance, went to the back of the cave. “Professor Bullfinch,” he called, his voice echoing in the chamber. “There’s an opening here. Plenty big enough for you to stand up in.”

  The Professor hastened to join him, and together they shone their lights into the space. “It’s a real tunnel, all right,” he said.

  Its floor slanted steeply downward, and was covered with loose gravel. The Professor took a cautious step or two, and then said, “I can hear something trickling. There may be a stream down there.”

  “Oh, boy!” Danny said. “A secret underground river!”

  He darted forward. His foot slipped in the gravel, and he lost his balance. He grabbed for the nearest support, which happened to be the front of the Professor’s jacket.
r />   The Professor went plunging down the slope, with Danny clinging to him. Somehow they managed to keep from falling. Sliding and swaying, they raced downward, their lights darting crazily as they waved their arms to keep their balance. Then, all at once, they hit a patch of wet clay.

  The Professor’s heels went out from under him.

  “I can’t—” he yelled.

  Thump! Down he went, with Dan on top of him.

  There was a long pause. At last, in a muffled voice, he finished: “—keep my balance. Would you mind taking your elbow out of my ear, Dan?”

  CHAPTER SEVEN

  The Underground Waterfall

  They disentangled themselves and got to their feet. The back of the Professor’s coat was covered with blue clay, which Danny tried vainly to wipe off.

  “I’m awfully sorry,” the boy said. “It was all my fault. I shouldn’t have rushed out ahead of you like that.”

  The Professor shook his head. “There are times when you are rather—uh—sudden, Dan,” he said, mildly. “However, this gravel is tricky stuff. And in cave exploring, I suppose we must expect a few spills.”

  Fortunately, their lights weren’t damaged. The Professor looked about for his C-ray. It lay close at hand, one corner buried in soft clay.

  “It seems to be all right,” said the Professor, examining it. “I hope none of the tubes have been broken.”

  He was about to snap it on and try it, when from the cave above them came a hail from Dr. Tresselt.

  “Ahoy, Bullfinch! Are you down there?”

  The Professor turned back and shouted, “Yes! Come on down.”

  Gravel began rattling along the slope and within a few moments their friends had joined them.

  Dr. Tresselt said, “Do you really think it was wise, Euclid, to go on ahead without telling the rest of us where you were going?”

  “Don’t be annoyed, my dear chap,” the Professor replied. “In theory you are absolutely correct, but this was a case where theory and practice didn’t go together. I didn’t even have time to yell ‘Help!’”

  Danny had been examining their surroundings, and he now broke in, “You were right, Professor. There is a stream.”

  They crowded round him. The clay bank ended in a flat strand of stone, below which flowed a shallow river some nine or ten feet wide. Smooth boulders stuck up out of it, and on its other shore rose a wall of glistening rock. The water was black in the lamplight, but when Joe shone the beam of his flashlight directly into it they could see that it was as clear as glass.

  “Hey, there are fish in this stream,” Joe said. “But golly, they look awfully pale. Aren’t they well?”

  “They’re just bleached out from living in the dark,” Irene said, leaning over to watch the slender white forms that darted in and out of the circle of light. “Do you think they’re blind, too, Dr. Tresselt?”

  The geologist nodded. “Possibly,” he said. He wasn’t looking into the water, however, but at the walls of the cavern. “You know,” he went on, “I think we are looking at the thing which dug out these caves in the first place.”

  “We are?” Danny cried. “Where is it?”

  “A machine?” said Joe. “Or a prehistoric monster?”

  “A kind of prehistoric monster,” Dr. Tresselt chuckled. “There it is—right at your feet.”

  Joe jumped back.

  “I know what you mean,” said Danny, grinning. “The river!”

  “Just so. The river cut its way through the soft limestone—of course, when I say ‘soft’ I mean that only in terms of other rocks—during millions of years, eating it away and making a bigger and bigger passage for itself.”

  “Then why doesn’t it still come out at the upper cave, where we entered?” Danny asked. “We saw the dry bed where it used to be, remember. What made it stop running up there?”

  “I think there must have been other streams tunneling below it,” Dr. Tresselt replied. “Or possibly an earthquake shifted the rock. Hard to say. Whatever the reason was, the bed of the river collapsed and the stream level dropped.”

  “Where do you think it comes out now?” Irene said. “Somewhere in the valley?”

  “Maybe at the reservoir,” Danny suggested. Dr. Tresselt flashed his light, first down the stream, then up. “It’s difficult to say. It could come out a long way below Midston.” He walked a little way upstream and paused. “Shh! Don’t I hear something?”

  They cocked their heads. At last, Irene said, “I can hear a kind of hollow, roaring sound.”

  “Yes, so can I,” said Danny.

  “A waterfall?” asked Professor Bullfinch.

  “I wouldn’t be surprised,” Dr. Tresselt answered.

  “Let’s go see,” Danny said. And before the others could answer, he was already trotting along the flat stone shore toward the distant sound.

  “Hey, wait!” called Joe. “Maybe it’s too risky. Maybe we’ll be washed away. Maybe it’s—oh, what’s the use?” he finished, shrugging. “Let’s go.”

  “Yes, since we’ve come this far,” the Professor said, smiling, “I must say, I wouldn’t mind seeing an underground waterfall myself. If that’s what it really is.”

  Irene and Joe soon caught up with Danny and the three made their way along the bank of the river, side by side. The water clucked and gurgled softly. Joe kept shining his light into it, and reflections shot up and sparkled from the walls and roof.

  “What I’d like to do,” Danny said, “is bring a boat here and travel right down the river. Wouldn’t that be fun?”

  “Fun?” Joe snorted. “We’d probably end up coming out of somebody’s water faucet.”

  “Oh, Joe. You’re always looking on the dark side of things,” Irene protested.

  “Well, what of it?” Joe gestured with his light at the gloomy cavern around them. “Where else would you look, down here?”

  “I suppose the chances are that it might be impossible to get all the way downstream,” Irene said. “The tunnel might get too low for a boat to get through. Or the water might drop down deeper and deeper.”

  “To the center of the earth,” Joe muttered. “And then we’d be boiled to death. Boiled Joe with cave sauce. What a way to end!”

  Danny laughed. “Well, don’t start planning your own menu, Joe. We haven’t even got a boat.”

  Joe shook his head. “If I know you, you’ll probably invent one before we get out of here,” he said. “Nothing but trouble.”

  The passage grew smaller so that they now had to go in single file. Columns of stone, some of them polished and smooth, rose before them and they had to pick their way slowly. The air grew damp and a cool, faint breeze touched their faces. The roaring, rushing noise was so loud it seemed to shake the very rocks.

  All at once Danny stopped, so abruptly that Irene bumped into him. She looked over his shoulder. Then she turned to Joe. “Look at this!” She had to yell to make herself heard, even though he was right behind her.

  In the light of their combined torches, a magical sight appeared. A curtain of diamonds was strung before them. Its foot was white foam in which floated rainbow-colored bubbles the size of soup bowls. It was not very high, but it had a majestic look, pouring from the roof of the cave and winding away between the ledges of shining stone.

  “It’s like fairyland,” Irene said. The boys nodded soberly.

  As they stood gazing in wonder, the two men caught up with them. They, too, stared at the lovely waterfall in silence for a long time.

  The Professor gave a long sigh. He shone his flashlight along the top of the falls, and they could see that the rocky roof came down almost to the water. The walls closed in, too, on either side.

  “It looks as though this is the end of the trip,” he said. “This is as far as we can go.”

  CHAPTER EIGHT

  The Bridge of S
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  They all moved back a little way to avoid the spray which was beginning to soak them, and sat down on a ledge from which they could look about in comfort. Professor Bullfinch pointed to the roof.

  “Icicles!” Joe exclaimed.

  The roof here was composed of flat slabs of stone, veined with darker green and pale blue. From it hung hundreds of what appeared to be pointing fingers, some of them a few inches long, some nearly a foot.

  “Stalactites,” Danny said. “I’ve read about them. They’re formed by water dripping from above, aren’t they, Professor?”

  “Yes. The water seeps through minerals and leaves deposits of them as it evaporates. It may take about ten years for an inch-long stalactite of the thickness of those on the roof to form. Thicker ones may take longer. Those, for instance—”

  He pointed with his lamp at the wall, some distance away and to one side of the waterfall. They saw several immense stalactites hanging down, perhaps two feet thick and as tall as a man.

  “Those may have taken a hundred thousand years to form,” said the Professor.

  “Whew! The ones up on the ceiling are babies, then,” Joe said. “Thirty- or forty-year-old babies.”

  “Yes. Probably they haven’t grown longer because there is a slight air current here caused by the rush of the falls. That would make the dripping water evaporate too quickly.”

  Danny got up. “I’d like to look at those big stalactites,” he said. He wandered off, his light throwing strange shadows from the stone and water.

  Joe pointed his own flashlight in Danny’s direction. “Look, Professor,” he said. “There’s an upside-down stalactite. One that got mixed up and grew the wrong way.”

  A pointed column grew out of the floor not far from where Danny was at that moment walking. It was almost as high as the boy himself, with a dazzling white streak down the side of it, like snow on a thin, steep mountain.

  “Ah, that kind we call stalagmites,” said Dr. Tresselt. “They are caused by water dropping on the floor and building secretions of minerals from the ground up.”