[21]Marian W. Smith, _Asia and North America Transpacific Contacts_ (Memoirs, Society for American Archaeology, vol. 18, no. 3 pt. 2, 1953). [22]Gordon F. Ekholm, “A Possible Focus of Asiatic Influence in the Late Classic Cultures of Mesoamerica,” in _Asia and North America Transpacific Contacts_ (1953), 72-89. Chapter 11 [1]Erland Nordenskiöld, _Modifications in Indian Customs Through Inventions and Loans_ (Comparative Ethnographical Studies, no. 8, 1930), 23-24. [2]Nordenskiöld, “Origin of the Indian Civilizations in South America,” in _The American Aborigines_ (1933), 278. [3]_Ibid._, 285. [4]Robert H. Lowie, _The History of Ethnological Theory_ (1937), 165. [5]Herbert J. Spinden, “The Origin and Distribution of Agriculture in America,” in _Source Book in Anthropology_ (1931), 228. [6]Carl Sauer, “American Agricultural Origins,” in _Essays in Anthropology_, ed. R. H. Lowie (1936), 281. [7]N. I. Vavilov, “Studies on the Origin of Cultivated Plants,” _Bulletin of Applied Botany_, vol 16, no. 2, pp. 218-219 (1926). S. M. Bukasov and others, “The Cultivated Plants of Mexico, Guatemala, and Colombia,” 47th Supplement to the _Bulletin of Applied Botany_, 1930. Other papers listed in Henry J. Bruman, “The Russian Investigations on Plant Genetics in Latin America and Their Bearing on Culture History,” _Handbook of Latin American Studies_ (1937), 287. [8]Bruman, _op. cit._, 451. [9]Sauer, _op. cit._, 288. [10]Bruman, _op. cit._, 456. [11]Richard S. MacNeish, “Agricultural Origins in Middle America and Their Diffusion into North America,” _Katunob_, vol. 1, no. 2 (1960), 29. [12]Harold S. Gladwin, _Excavations at Snaketown_ (Medallion Papers, Gila Pueblo, no. 26, 1937), 2:79. [13]Bruman, _op. cit._, 456-457. [14]O. F. Cook, “Staircase Farms of the Ancients,” _National Geographic Magazine_, 29:513 (1916). [15]P. C. Mangelsdorf and R. G. Reeves, _The Origin of Indian Corn and Its Relatives_ (Bulletin No. 574, Texas Agricultural Experiment Station, 1939), 7. [16]_Ibid._, 7. [17]_Ibid._, 8, 7. [18]Sauer, _op. cit._, 292. [19]G. N. Collins, “The Phylogeny of Maize,” _Bulletin, Torrey Botanical Club_, 57:203 (1930). [20]Bruman, _op. cit._, 457. [21]Sylvanus G. Morley, _The Ancient Maya_ (1946), 386. [22]MacNeish, _op. cit._, 27. [23]Paul C. Mangelsdorf, “Ancestor of Corn,” _Science_, 128:1314 (1958). [24]Paul C. Mangelsdorf and C. Earle Smith, Jr., “A Discovery of Primitive Maize in New Mexico,” _Journal of Heredity_, 40:39-43 (1949), and “New Archaeological Evidence on Evolution in Maize,” _Harvard University Botanical Museum Leaflets_, vol. 13, no. 8, 213-247 (Mar., 1949). [25]Willard F. Libby, _Radiocarbon Dating_ (1955), 133. [26]Junius Bird, “South American Radiocarbon Dates,” in _Radiocarbon Dating_ (Memoirs, Society for American Archaeology, vol. 17, no. 1, pt. 2, 1951), 48.