It was not the water which little by little had hollowed it.
Pluto and not Neptune had bored it with his own hand, and on the wall traces of an eruptive work could be distinguished, which all the washing of the water had not been able totally to efface.
The settlers descended very slowly.

They could not but feel a certain awe, in this venturing into these unknown depths, for the first time visited by human beings.

They did not speak, but they thought; and the thought came to more than one, that some polypus or other gigantic cephalopod might inhabit the interior cavities, which were in communication with the sea.

However, Top kept at the head of the little band, and they could rely on the sagacity of the dog, who would not fail to give the alarm if there was any need for it.
After having descended about a hundred feet, following a winding road, Harding who was walking on before, stopped, and his companions came up with him.

The place where they had halted was wider, so as to form a cavern of moderate dimensions.