Progress, 228. Races, human, 19; Paleolithic 180; Neolithic 193. Religion, Paleolithic, 208; Neolithic, 206, 276; of lake-dwellings, 84; of Indo-Europeans, 268, 276. Rinnekalns, 47. Ritual, 210. River-valleys as trade-routes, 143, 190. Roman law, 258. Sahara, once well-watered, 22. Salt, 139. "_Schuhleistenbeil_" (mattock), 137. Semites, 19, 22, 106. Sheep, 78, 91. Shell-heaps, 40, 172, 197. Siwalik strata, 14. Social development, 85. Steppe, 27, 32, 65, 189. Stutzheim, 57, 59. Susa, 99. Taboo, 211. Tertiary period, 9. Trade, 144; routes, 152. Tribal education, 275. Tridachna shells in Europe, 147. Tumuli, 116. Tundra, 26, 36. Weaving, 83. Wheat, 80, 94. Women, position in Neolithic time, 224, 249. Yoldia Epoch, 37, 162. * * * * * Transcriber's Note: In the Bibliography, p. 294, under "CHAPTER I", there was no number 4 in the original.