[40.] Osborn, H. F. Men of the Old Stone Age. New York, 1915.

[41.] Ranke, J. Der Mensch. Leipsic, 1900.

[42.] Geikie, J. Antiquity of Man in Europe. Edinburgh, 1914.

[43.] —— The Great Ice Age. 3d ed. London, 1894.

[44.] Reinhardt, L. Der Mensch zur Eiszeit in Europa. Munich, 1906.

[45.] Geikie, J. “Tundras and Steppes of Prehistoric Europe,” Smithson. Report, 1897-98, 321.

[46.] Nehring, A. Tundren u. Steppen der Jetzt-und Vor-zeit. Berlin, 1890.

[47.] Schöetensack, O. Der Unterkiefer des “Homo Heidelbergensis.” Leipsic, 1908.

[48.] MacCurdy, G. G. “The Eolith Problem,” Amer. Anth., N. S., VII, 1905, 425.

[49.] Sollas, W. J. Ancient Hunters. 2d ed. London, 1915.