“But surely, then, like other fossil wood, it must be as hard as stone, and cannot float?”

“Sometimes that may happen; some of these woods become true anthracites; but others, such as this, have only gone through the first stage of fossil transformation. Just look,” added my uncle, throwing into the sea one of those precious waifs.

The bit of wood, after disappearing, returned to the surface and oscillated to and fro with the waves.

“Are you convinced?” said my uncle.

“I am quite convinced, although it is incredible!”

By next evening, thanks to the industry and skill of our guide, the raft was made. It was ten feet by five; the planks of surturbrand, braced strongly together with cords, presented an even surface, and when launched this improvised vessel floated easily upon the waves of the Liedenbrock Sea.