“Another entrance!” they echoed. “Where?”
By way of answer the learned Parson seized Mark by the shoulder and forced him over toward what seemed to be the blank wall of rock in front of them. Stanard pointed and Mark followed the direction of his finger and understood. A faint chink in the rock where the bright light of day strayed in told the story with all possible plainness.
“It leads out into the open,” Mark admitted, after a moment’s thought. “Any one can see that. But how do you know it is an entrance?”
“It is evident to the most superficial observation,” replied the Parson, “that the walls of the cave are of a different sort from the rock we have before us. The former is a species of sandstone of quaternary origin, while the latter is a kind of granite technically known——”
“What has that got to do with it?” growled Texas.
“Yes, yes!” roared the rest. “Go on!”
“I am going,” said Stanard. “Ahem! By Zeus! As I was about to remark, this bowlder, for such it is, is evidently of glacial origin and therefore——”
“For heaven’s sake!” cried Mark, laughing in spite of himself. “Do you mean to say that it’s a loose rock?”
“Precisely,” said the geologist. “That is to say——”
Then the matter came to an abrupt end. Texas, who had been dancing about with impatience, caught the meaning of the words “loose,” and with a bound flung himself against the bowlder.