To understand what followed, it must be borne in mind that, through circumstances hereafter to be explained, we were not really where the Professor supposed we were. In fact we were not upon the north shore of the sea.
“Now let us start upon fresh discoveries,” I said.
And leaving Hans to his work we started off together. The space between the water and the foot of the cliffs was considerable. It took half an hour to bring us to the wall of rock. We trampled under our feet numberless shells of all the forms and sizes which existed in the earliest ages of the world. I also saw immense carapaces more than fifteen feet in diameter. They had been the coverings of those gigantic glyptodons or armadillos of the Pliocene period, of which the modern tortoise is but a miniature representative. The soil was besides this scattered with stony fragments, boulders rounded by water action, and ridged up in successive lines. I was therefore led to the conclusion that at one time the sea must have covered the ground on which we were treading. On the loose and scattered rocks, now out of the reach of the highest tides, the waves had left manifest traces of their power to wear their way in the hardest stone.
This might up to a certain point explain the existence of an ocean forty leagues beneath the surface of the globe. But in my opinion this liquid mass would be lost by degrees farther and farther within the interior of the earth, and it certainly had its origin in the waters of the ocean overhead, which had made their way hither through some fissure. Yet it must be believed that that fissure is now closed, and that all this cavern or immense reservoir was filled in a very short time. Perhaps even this water, subjected to the fierce action of central heat, had partly been resolved into vapour. This would explain the existence of those clouds suspended over our heads and the development of that electricity which raised such tempests within the bowels of the earth.