"The Doctor seems interested in that cliff," said one of the boys.
"Yes, and he's ruining the edge of his axe upon it," said another. "I suppose he has found something of geologic interest there."
Just then the Doctor quitted his work on the bank, removed his hunting shirt, tied it up by the neck and filled it full of the blocks he had chopped out of the bank. It held about half a bushel. Going to the fire, he emptied the mass upon it, and watched for results with eagerness. The slate rock, as the boys had called it,—burned slowly and gave out a good deal of heat.
Then the Doctor addressed himself to his breakfast, but he ate in silence. After he had done, he said to Tom—for he and Tom had become special cronies—"Tom, I wish you would take two of the boys with you this morning, go down to the railroad camps and buy four or five picks and four or five shovels."
"Certainly, Doctor," answered Tom. "But what is it you want with the picks and shovels?"
"I want to dig into that bank. I want to find out whether what I suspect is true or not."
"What is it you suspect, Doctor?" asked Jack eagerly.
"I suspect that that slate rock bank is the outcrop of one of the very richest coal mines in America. I may be wrong, but if you'll go down and get the picks and shovels, we'll soon find out."
"But why not all go down and bring back some miners with us?"
"Because we don't want any miners and especially we don't want anybody to 'jump our claim'—that is to say, to come here and claim a royalty on the plea that he first discovered the mine. Boys, I don't think we'll any of us get home as soon as we expected. This is something worth staying for, and fortunately we are now within easy reach of supplies."