In this and other instances, cut bones afford one of the most certain tests of the presence of man. The bones tell their own tale, and their geological age can be certainly identified. Sharp cuts could only be made on them while the bones were fresh, and the state of fossilization, and presence of dendrites or minute crystals alike on the side of the cuts and on the bone, negative any idea of forgery. The cuts can be compared with those on thousands of undoubted human cuts on bones from the reindeer and other later periods, and with cuts now made with old flint knives on fresh bones. All these tests have been applied by some of the best anthropologists of the day, who have made a special study of the subject, and who have shown their caution and good faith by rejecting numerous specimens which did not fully meet the most rigorous requirements, with the result that in several cases there could be no reasonable doubt that the cuts were really made by human implements guided by human hands. The only possible alternative suggested is, that they might have been made by gnawing animals or fishes. But as Quatrefages observes, even an ordinary carpenter would have no difficulty in distinguishing between a clean cut made by a sharp knife, and a groove cut by repeated strokes of a narrow chisel; and how much more would it be impossible for a Professor trained to scientific investigation, and armed with a microscope, to mistake a groove gnawed out by a shark or rodent for a cut made by a flint knife. No one who will refer to Quatrefages' _Hommes fossilés_, and look at the figures of cut bones given there from actual photographs, can feel any doubt that the cuts there delineated were made by flint knives held by the human hand. In addition to this instance of St. Prest, Quatrefages in his _Histoire des Races Humaines_, published in 1887, and containing the latest summary of the evidence generally accepted by French geologists as to Tertiary man, says that, omitting doubtful cases, the presence of man has been signalized in deposits undoubtedly Tertiary in five different localities, viz. in France by the Abbé Bourgeois, in the Lower Miocene of Thenay near Pontlevoy (Loir-et-Cher); by M. Rames at Puy Courny near Aurillac (Cantal), in the Upper Miocene; in Italy by M. Capellini in the Pliocene of Monte Aperto near Sienna, and by M. Ragazzoni in the Lower Pliocene of Castelnedolo near Brescia; in Portugal by M. Ribiero at Otta, in the valley of the Tagus, in the Upper Miocene. [Illustration: CUTS WITH FLINT KNIFE ON RIB OF BALÆONOTUS--PLIOCENE. From Monte Aperto, Italy. (Quatrefages, _Histoire des Races Humaines_.)] [Illustration: CUT MAGNIFIED BY MICROSCOPE.]