Chapter II: Part I

I THE ABSTRACT IDEA 11
II HISTORY OF THE IDEA 14
III FACT NUMBER ONE 20
IV FACT NUMBER TWO 24
V TURNED UPSIDE DOWN 27
V FACT NUMBER FOUR 31
VII EXTINCT SPECIES 34
VIII SKIPPING 42

PART II

IX GRAVEYARDS 53
X CHANGE OF CLIMATE 64
XI DEGENERATION 70
XII FOSSIL MEN 74
XIII INDUCTIVE METHODS 81
APPENDIX 89