[46]These “teeth” show a peculiar gloss produced by the silica in the stalks of grasses so that we are certain that they were used for cutting cereals. (Cecil E. Curwen in _Antiquity_, IV [1930], 184-6; IX [1935], 62-6.) [47]G. Caton-Thompson and E. W. Gardner, _The Desert Fayum_ (London, 1934), 45 and Plates XXVI, XXVIII, XXX. [48]_Journal of Near Eastern Studies_, IV (1945), 269, 274, and Fig. 37. [49]R. Girshman, _Fouilles de Sialk_, I (Paris, 1938), 17 ff. and Plates VII, LIV. [50]Walter B. Emery, _The Tomb of Hemaka_ (Cairo, 1938), 33 and Plate 15. [51]W. M. Flinders Petrie, _Tools and Weapons_ (London, 1917), 46 and Plate LV, 7. [52]P. Delougaz, _The Temple Oval at Khafajah_ (Chicago, 1940), 30-1, Figs. 26, 27. [53]C. F. C. Hawkes, _The Prehistoric Foundations of Europe_ (London, 1940), 82-4. [54]C. Daryll Forde, _Habitat, Economy and Society_ (London, 1934), 35: “In Owen’s valley several groups took advantage of favourable conditions to irrigate patches of ground. The growth of bulbous plants and grasses is patently more luxuriant wherever abundant water reaches them, and this was achieved artificially by diverting from their narrow channels the snow-fed streams flowing down from the Sierra Nevada. In spring, before the streams rose with snow-melt, a dam of boulders, brushwood and mud was thrown across a creek where it reached the valley floor.... Above the dam one or two main ditches, sometimes more than a mile long, were laboriously cut with long poles to lead the river water out on the gently sloping ground over which it was distributed by minor channels.... After the harvest the main dam was pulled down.... There was, however, no attempt at planting or working the soil, and none of the cultivated plants grown to the south of the Colorado were known.” [55]V. Gordon Childe, _Man Makes Himself_, 109, states that some of these villages, when completely excavated, covered no more than from 1½ to 6½ acres, lodging from eight to ten households. In _The Town Planning Review_, XXI (1950), 6, he states that sixteen to thirty houses was the normal figure of a local group which he estimates at 200 to 400 souls. [56]John Burckhardt, _Travels in Nubia_, 2nd ed. (London, 1822), 348-50. [57]Percy E. Newberry, _Egypt as a Field of Anthropological Research_, Smithsonian Institution, Annual Report for 1924 (Washington, 1925), 435-59.