“Why, it was simply buried in fine mud, which first protects it from the air, (and consequent immediate decay), then gradually fills every pore of every bone, till by the time the mud has turned to stone, the bones are ossified. Of course the animal matter has all dissolved away by this time. Now if this mud that filled the pores happened to be silica, (a sandy formation), it is possible to eat the surrounding limestone away with acids and uncover the silica formation, see, old kid?”
“Aw, that stuff makes my head ache,” protested Tim. “If I see any ossified bones lying around, or even a footprint or leaf print in the stone, I’ll know I’ve found a fossil. But I thought we were chasing fire-bugs.”
“The impatience of youth!” Ace playfully squelched him, from the vantage point of his slight seniority.
“What does the Bible say,” laughed the Ranger, “about truth from the mouths of babes?” And he arose a bit stiffly,—for he had had a strenuous time of it the past few days, and the cave damp had set his tired limbs to aching.
For upwards of an hour they followed dark and winding passageways, (rats and lizards and occasional colonies of bats fleeing before them), naturally without the slightest sign of the fugitives, when they came to another grotto, the loveliest they had yet seen. It might have been a fairy cavern, aglitter with pure crystal. The carved prisms shone dazzlingly in the light of the carbide lamp, and the boys stuffed their pockets with some of the jewel-like bits that had fallen to the floor.
From this they presently entered into what seemed like a Gothic cathedral, with a dome whose highest point must have been several hundred feet above. The boys were fairly awed by its beauty, while the Ranger’s eyes gleamed appreciatively. On the walls were what might have been carvings of flowers and lacework, creamy to smoke color, gypsum, Ace told them.
“Are these fossils?” demanded Ted excitedly.
“I should say not, you poor fish!—You ichthyosaurus,” laughed Ace teasingly.
“You what?” asked the Ranger.
“That means ancient fish.”