These rough specimens of wrought flint, in which Boucher de Perthes already recognised a kind of hatchet, presented very indistinct traces of chipping, and the angles were blunted; their flattened shape, too, differed from that of the polished hatchets, the only kind that were then known. It was certainly necessary to see with the eyes of faith in order to discern the traces of man's work. "I," says the Abbeville archæologist, "had these 'eyes of faith,' but no one shared them with me." He then made up his mind to seek for help in his labour, and trained workmen to dig in the diluvial beds. Before long he was able to collect, in the quarternary beds at Abbeville, twenty specimens of flint evidently wrought by the hand of man. In 1842, the Geological Society of London received a communication from Mr. Godwin Austen, who had found in Kent's Hole various wrought objects, accompanied by animal remains, which must have remained there since the deluge. In 1844, appeared Lund's observations on the caverns of Brazil. Lund explored as many as 800 caves. In one of them, situated not far from the lake of Semidouro, he found the bones of no less than thirty individuals of the human species, showing a similar state of decomposition to that of the bones of animals which were along with them. Among these animals were an ape, various carnivora, rodents, pachyderms, sloths, &c. From these facts, Lund inferred that man must have been contemporaneous with the megatherium, the mylodon, &c., animals which characterised the quarternary epoch. Nevertheless, M. Desnoyers, librarian of the Museum of Natural History at Paris, in a very learned article on 'Grottos and Caverns,' published in 1845 in the 'Dictionnaire Universel d'Histoire Naturelle,' still energetically expressed himself in opposition to the hypothesis of the high antiquity of man. But the discoveries continued to go on; and, at the present time, M. Desnoyers himself figures among the partisans of the antediluvian man. He has even gone beyond their opinions, as he forms one among those who would carry back to the tertiary epoch the earliest date of the appearance of our species. In 1847, M'Enery found in Kent's Hole, a cavern in England, under a layer of stalagmite, the remains of men and antediluvian animals mingled together. The year 1847 was also marked by the appearance of the first volume of the 'Antiquités Celtiques et Antédiluviennes,' by Boucher de Perthes; this contained about 1600 plates of the objects which had been discovered in the excavations which the author had caused to be made since the year 1836. The strata at Abbeville, where Boucher de Perthes carried out his researches, belong to the quaternary epoch.