The four were forced to proceed single file, for the path was narrow and branches of low-hanging trees formed an archway above their heads. Presently, Doris who was in the lead stopped short and gave an exclamation of surprise. “What’s the matter?” Kitty demanded. “We’ve come to the jumping off place! And just see what I’ve discovered. A cave!” Kitty thought her chum was only joking, but as she came up behind her she saw for herself the tiny opening in the side of the cliff. Dave and Marshmallow crowded up, the latter becoming greatly excited. “Jumping snakes!” he exclaimed. “I never heard about this cave. I wonder what’s inside?” He thrust his head in at the opening but could see nothing, as his eyes were unaccustomed to the darkness. “If we only had a flashlight!” he declared. “It would be fun to explore it.” “Maybe it’s inhabited by bears,” Kitty suggested nervously. “Never heard of any around here,” Marshmallow insisted. “Say, we can’t go home without seeing the inside.” “I think there’s a flashlight in the car,” Dave told him. “I’ll see.” The girls and Marshmallow waited impatiently for Dave to return. Presently, he came back with the flashlight. “Wouldn’t it be grand if we’d find buried treasure?” Doris laughed. “I could use some money all right, and I don’t know of any more delightful way to obtain it.” She did not really hope that any such adventure would befall them, but Kitty’s eyes grew round at the mere mention of treasure. “Who’s to go first?” Doris asked. “Let me,” Marshmallow begged. Dave handed him the flashlight, and after an instant’s hesitation he again thrust his head and shoulders through the opening. It was only a small aperture, and Marshmallow grunted as he squeezed through. “You’re too fat,” Doris called after him. “You may never get out again.” There was no response from the inside of the cave and Kitty, suddenly becoming alarmed, called anxiously: “Marshmallow! Marshmallow!” “I’m right here,” came a muffled voice. “Come on in.” “What do you see?” Doris demanded. “It looks like a cracking big cave.” Somewhat reassured, the girls wormed their way through the opening and Dave brought up the rear. It was pitch dark inside, but the beam of Marshmallow’s light furnished a faint illumination. “Follow me,” Marshmallow commanded. He led the way deeper into the cavern. The cave consisted of two chambers, and as the four friends entered the second room Marshmallow flashed his light over the ceiling. They saw strange formations resembling icicles hanging from above. “Stalactites!” Doris exclaimed. “Aren’t they odd?” Kitty cried. “What causes them anyway?” “I’ve read that stalactites are caused by the dripping of water which contains carbonate of lime,” Doris explained. “Folks, I guess we’ve seen all the sights,” Marshmallow, who had gone on a short way ahead, announced. “It isn’t as large a cave as I thought.”