[19]L. S. B. Leakey, _The Stone Age Cultures of Kenya Colony_ (1931), 103-104, pl. 11. [20]E. B. Sayles, _An Archaeological Survey of Texas_ (Medallion Papers, Gila Pueblo, no. 17, 1935), table 9. Wm. Duncan Strong, “Finding the Tomb of a Warrior-God,” _National Geographic Magazine_, 91:459 (1947). [21]Childe, “Changing Methods and Aims in Prehistory,” _Proceedings, Prehistoric Society_, 1935, 8. [22]Seton Lloyd and Fuad Safar, “Tel Hassuna: Excavations by the Iraq Government Directorate General of Antiquities, in 1943 and 1944,” _Journal of Near Eastern Studies_, 4:255-289 (1945). Chapter 4 [1]John Playfair, _Illustrations of the Huttonian Theory of the Earth_ (1802), 388-389. [2]A. Bernhardi, “Wie kamen die aus dem Norden stammenden Felsbruchstücke und Geschiebe, welche man in Norddeutschland und den benachbarten Ländern findet, an ihre gegenwärtigen Fundorte?” _Jahrbuch für Mineralogie, Geognosie, und Petrefaktenkunde_, 3:257-267 (1832). [3]Albrecht Penck and Eduard Brückner, _Die Alpen im Eiszeitalter_ (1901-1909). [4]Ernst Antevs, _Late Glacial Correlations and Ice Recession in Manitoba_ (Canada Geological Survey, Memoir 168, 1931), 2, 33. [5]Richard F. Flint, “Chronology of the Pleistocene Epoch,” _Quarterly Journal, Florida Academy of Sciences_, 8:3-4 (1945). [6]Ernst Antevs, _The Last Glaciation_ (American Geographical Society, Research Series, No. 17, 1928), 74-82. R. A. Daly, _The Changing World of the Ice Age_ (1934), 46. Richard F. Flint, _Glacial Geology and the Pleistocene Epoch_ (1947), 334-335. [7]Eduard Brückner, “Postglaziale Klimaänderungen und Klimaschwankungen im Bereich der Alpen,” _Die Veränderungen des Klimas seit dem Maximum der letzten Eiszeit_ (Stockholm, 1910), 108. [8]Milutin Milankovitch, “O Rasporedu suneeve Radijacije na Povrsini Zembljie” (On the Distribution of Solar Radiation on the Surface of the Earth), _Glas Srpske K. Akad._, 91:101-179 (1913), and “Neue Ergebnisse der astronomischen Theorie der Klimaschwankungen,” _Bulletin, Royal Serbian Academy of Science_, 1938, p. 4. [9]Frederick E. Zeuner, _The Pleistocene Period_ (1945), 167. [10]Kirtley F. Mather, _Sons of the Earth_ (1930), 106. [11]Zeuner, _op. cit._, 161. [12]Maurice Ewing and William L. Donn, “A Theory of Ice Ages,” _Science_, 123:1061-1066 (1956), and “A Theory of Ice Ages II,” _Science_, 127:1159-1162 (1958), and “Theory of Ice Ages,” _Science_, 129:464-465 (1959). [13]George C. Simpson, “World Climate During the Quaternary Period,” _Quarterly Journal, Royal Meteorological Society_, 60:425-478 (1934), and “Ice Ages,” _Nature_, 141:591-598 (1938)—reprinted in _Annual Report, Smithsonian Institution_, 1938, 289-302. [14]Zeuner, _op. cit._, 163. [15]_Ibid._, 164-165. [16]A. Vayson de Pradenne, _Prehistory_ (1940), 84-85. Chapter 5