The World Before the Deluge

by Louis Figuier

The mouth or entrance to the cave originated, in the first instance, in an open joint or fissure in the Devonian limestone, which became widened by water flowing backwards and forwards, and was partly enlarged by the atmospheric water, which percolated through the cracks, fissures, and open joints in the overlying rock. The pebbles, forming the lowest deposit in the cave, were ordinary shingle or beach-gravel, washed in by the waves and tides. The cave-earth was the residual part of the limestone rock, after the calcareous portion had been dissolved and carried away in solution; and the stalactite and stalagmite were derived from the lime deposited from the percolating water.

With regard to bone-caves generally, it would seem that, like other such openings, they are most common in limestone rocks, where they have been formed by water, which has dissolved and carried away the calcareous ingredient of the rock. In the case of the Brixham cave, the mode of action of the water could be clearly traced in two ways: first, in widening out the principal passages by the rush of water backwards and forwards from the sea; and, secondly, by the infiltration and percolation of atmospheric water through the overlying rock. In both cases the active agents in producing the cave had taken advantage of a pre-existing fissure or crack, or an open joint, which they gradually enlarged and widened out, until the opening received its final proportions.

The cave presented no appearance of ever having been inhabited by man; or of having been the den of Hyænas or other animals, like Wookey Hole in the Mendips, and some other bone-caves. The most probable supposition is, that the hind quarter of the Bear and other bones which were found in the cave-earth, had been washed into the cave by the sea, in which they were floating about.

We draw some inferences of the greatest interest and significance from the Brixham cave and its contents.

We learn that this country was, at one time, inhabited by animals which are now extinct, and of whose existence we have not even a tradition; that man, then ignorant of the use of metal, and little better than the brutes, was the contemporary of the animals whose remains were found in the cave, together with a rude flint-implement—the only kind of weapon with which our savage ancestor defended himself against animals scarcely wilder than himself.

We also learn that after the cave had been formed and sealed up again, as it were, together with all its contents, by the deposition of a solid crust of stalagmite—an operation requiring a very great length of time to effect—the Reindeer (Cervus Tarandus) was indigenous to this country, as is proved by the occurrence of an antler of that animal which was found lying upon, and partly imbedded in, the stalagmite forming the roof or uppermost, that is, the latest formed, of the cave-deposits.

Lastly, we learn that, at the time the cave was formed, and while the land was inhabited by man, that part of the country was lower by ninety-five feet than it is now; and that this elevation has probably been produced so slowly and so gradually, as to have been imperceptible during the time it was taking place, which extended over a vast interval of time, perhaps over thousands of years.

Perhaps it may not be out of place here to describe the mode of formation of bone-caves generally, and the causes which have produced the appearances these now present.

Caves in limestone rocks have two principal phases—one of formation, and one of filling up. So long as the water which enters the cavities in the course of formation, and carries off some of the calcareous matter in solution, can find an easy exit, the cavity is continually enlarged; but when, from various causes, the water only enters in small quantities, and does not escape, or only finds its way out slowly, and with difficulty, the lime, instead of being removed, is re-deposited on the walls, roof, sides, and floor of the cavity, in the form of stalactites and stalagmite, and the work of re-filling with solid carbonate of lime then takes place.

Encouraged by the Brixham discoveries, a congress of French and English geologists met at Amiens, in order to consider certain evidence, on which it was sought to establish as a fact that man and the Mammoth were formerly contemporaries.