“Fossils,” explained Ace, (fresh from first-year geology), “are any remains of plants or animals that lived, either on land or in the sea, in ancient times. A lot of those we find to-day were shell-fish and other marine life.”
“Gee!” grinned Ted, “doesn’t he talk like a professor? I’m going to call you professor after this, old Scout!”
“Go on,” the Ranger urged, ignoring this sally, “I’m interested.”
“So am I, honestly,” amended Ted contritely.
“There were land animals, too, that got buried in the accumulating sediments and fossilized. Times when the ocean over-ran the land, they got drifted into it, and sank, and got buried under the sands that made our sandstones––”
“This floor is sandstone!” interpolated Ted.
“Yes. Or they got buried in the ground-up shells that made our limestone,—like the walls of the cave,—or some of them were buried in mud.”
“I suppose,” offered Ted facetiously, “that the mud made mudstones,” and he laughed till his voice echoed and reëchoed startlingly.
“Ha, ha! You’re right!” Ace turned the laugh on him. “Go to the head of the class. I’ll show you mudstone when we come to it.”
“Why, then,” ventured the Ranger, “this must be a topping place to find fossils.”