12. Outline tracing of human skull from Le Moustier 40 13. Outline tracings of jawbones from Mauer and Le Moustier 41 14. Outline tracings of jawbones from Mauer, La Naulette, etc. (From Frizzi) 42 15. Outline tracings of jawbones, (A) ancient Briton (B) Le Moustier (C) Mauer 43 16. Outline tracings of the Forbes Quarry (Gibraltar) skull. (From Sera) 48 17. Human skull of the Grimaldi-type. (From Birkner) 51 18. Outline tracings of skulls from Galley Hill etc. (From Klaatsch) 58 19. Section of the strata at Trinil in Java. (From Dubois) 64 20. View of the Mauer sand-pit. (From Birkner) 65 21. Section of the Krapina rock-shelter. (From Birkner) 69 22. Plan of the cave at La Chapelle-aux-Saints. (From Boule) 72 23. Two sections of the Grotte des Enfants, Mentone. (From Boule) 77 24. Chart of the relative duration of Miocene, Pliocene, and Pleistocene time. (From Penck) 107 25. Chart of oscillations of snow-level in the Glacial period. (From Penck) 119 26. Outline tracings of skulls of Pithecanthropus etc. (From Dubois) 129 27. Position of Palaeolithic Man in the scale of evolution. (From Cross) 131 28. Thigh-bones arranged to illustrate Klaatsch's theory. 136 29. The human skeleton found beneath the Boulder-clay at Ipswich. (From a drawing by Dr Keith, reproduced with permission) 153 CHAPTER I THE PRECURSORS OF PALAEOLITHIC MAN Our knowledge of prehistoric man is based naturally upon the study of certain parts of the human skeleton preserved in a fossil state. In addition to these materials, other evidence is available in the form of certain products of human industry. These include such objects as implements of various kinds, owing their preservation to the almost indestructible nature of their material, or again artistic representations, whether pictorial or glyptic. The evidence of the bones themselves will be considered first, partly for convenience and partly in view of the cogency possessed by actual remains of the human frame. Other branches of the subject will come under review afterwards.