It is the old argument of Paley, reproduced in a form undreamt of in his philosophy. “If,” he might have said, “in digging into a bank of gravel we find a flint, we do not pause to ask whence it came; but if our spade strike on a watch?”——In the age of the Flint-Folk mechanical ingenuity expended itself for other purposes than the manufacture of time-measurers; but if the artificial origin of the implements of the drift, and their consequent indications of the presence of man, be acknowledged, our greatest difficulty is the remoteness of the period which they seem to indicate. Worked flints and other assumed human industrial remains have now been recovered from caverns, in various countries of Europe, as in the caves of Engis and Chokier, near Liége; at Mont Salève, Geneva; in the south of France, in Belgium, and in England: in every case so mingled with remains of the mammoth, rhinoceros, hyæna, and other extinct mammals, as to lead to the conviction of their contemporaneous deposition. Recent carefully conducted explorations in the Devonshire caves have resulted in seemingly indisputable proof that English flint-implements of the Amiens type are coeval with the extinct fauna; and that consequently the presence of their manufacturers must be assigned to periods prior to the successive inundations and depositions by which Brixham cave was gradually filled with layers of water-worn gravel, silt, or cave-earth, bone breccia, and solid floorings of carbonate of lime. The rudeness of many of the worked flints has suggested the idea of their accidental origin; but the most diligent search in the heaps of chalk-flints broken for the roads, in France or England, or crushed _in situ_ by subterranean movements, as in the Isle of Wight, has failed to recover a single specimen resembling even the rudest implements of the drift; whereas, in the ancient flint pits of the Shawnees, and probably of the Mound-Builders of Ohio,—to which I shall again refer,—I have collected fractured flints of precisely the same types as those familiar to us among the rudest drift implements. They differ for the most part in size, and also in type, from those found in early British or Danish grave-mounds; but artificial origin and inventive design are as obvious in the one as in the other.