"I was not speaking in a figurative way, but in plain, downright English.

That really is part of an ancient gold-mine, in which the water has collected in course of time." "Really?
Are you sure ?" said the Colonel.
"Yes, sir," replied Denham.

Then in a few words he told the Colonel that we had discovered two shafts within the walls, as well as the old furnace-house and the ingot-moulds.
"You astound me," said the Colonel.

"Here, come along and let me see." He followed Denham, and I went too, as one of the discoverers.

The Colonel examined everything with the utmost interest.
"Not a doubt about it," he said at last.