“All around the carapace,” says Ameghino, “in the reddish agglomerate of the original soil lay charcoal cinders, burnt and split bones, and flints. Digging beneath this, a flint implement was found, with some long split llama and stag bones, which had evidently been handled by man, with some toxodon and mylodon teeth.” Fig. 49 represents the now extinct mylodon. Some time afterwards, the discovery of another carapace under similar conditions added weight to Ameghino’s supposition.1 In the midst of the pampas, those vast treeless plains, where no rock or accident of conformation affords shelter from heat or cold or a hiding-place from wild beasts, man was not at a loss; he hollowed out for himself a hole in the earth, roofing it over with the shell of a glyptodon, and securing a retreat where he could be safe at least for a time. [Illustration: 49.] Mylodon robustus. It was not until later, driven to do so by the cold, that man learnt to use the natural caves hollowed out in limestone rocks, either in geological convulsions or by the quieter action of water. The absence in the caves which have been excavated in America of implements of the Chelléen type, the most ancient known as yet, would point to this conclusion, though it is impossible to fix the earliest date of their occupation. This date, moreover, varies very much in different localities. The earth was but gradually peopled, and our ancestors penetrated into different countries in successive migrations. Some caves have recently been discovered in Wales, in the midst of Glacial deposits.2 The Boulder Clay and marine drift on neighboring heights are incontrovertible proofs of the submergence of this region, when Great Britain was almost completely covered with ice. Excavations made in 1886 have brought to light a series of deposits, one above the other, the gravel and red earth containing Quaternary bones and worked flints, whilst the stalagmite and ooze are evidently of more recent origin. This is the usual state of things in all the English eaves; but in those of the Clyde, the bone beds had been disturbed and mixed with striated pebbles and Glacial drift. From this Hicks, who superintended the excavations, concluded that man and the Quaternary animals had lived in those caves before the Glacial epoch, and before the great submergence, which in some places was no less than some 1,300 feet below the present level of the sea. If this were so, it would be one of the most ancient proofs not only of the presence of man, but also of the kind of habitation he first dwelt in. These conclusions have, however, been hotly disputed. M. Arcelin3 remarks that there are in England two exceptional geological landmarks, the Forest Bed representing the last Pliocene formations, and the River Gravels, which are the most ancient Quaternary deposits. Between the two, we find the Boulder Clay of Glacial origin. Now the fauna of the caves of the