“The rain must go somewhere,” I repeated.

“He keeps a firm grip upon actuality. The only drawback is that we have conclusively proved by ocular demonstration that there are no water channels down the rocks.”

“Where, then, does it go?” I persisted.

“I think it may be fairly assumed that if it does not come outwards it must run inwards.”

“Then there is a lake in the center.”

“So I should suppose.”

“It is more than likely that the lake may be an old crater,” said Summerlee. “The whole formation is, of course, highly volcanic. But, however that may be, I should expect to find the surface of the plateau slope inwards with a considerable sheet of water in the center, which may drain off, by some subterranean channel, into the marshes of the Jararaca Swamp.”