I had not gone a hundred paces before incontestable proofs presented themselves. It could not be otherwise, for in the Silurian age the seas contained at least fifteen hundred vegetable and animal species. My feet, which had become accustomed to the indurated lava floor, suddenly rested upon a dust composed of the debris of plants and shells. In the walls were distinct impressions of fucoids and Lycopodites.

Professor Liedenbrock could not be mistaken, I thought, and yet he pushed on, with, I suppose, his eyes resolutely shut.

This was only invincible obstinacy. I could hold out no longer. I picked up a perfectly formed shell, which had belonged to an animal not unlike the woodlouse: then, joining my uncle, I said:

“Look at this!”

“Very well,” said he quietly, “it is the shell of a crustacean, of an extinct species called a trilobite. Nothing more.”