Manchester Memoirs, Vol. Ix. (1916), No. 6. 11 



eight feet high, but toward the top of the mountains they 

 often increase to fifteen feet. Though lined without 

 mortar, they are kept in perfect repair. Reservoirs filled 

 with water from the two rainy seasons supply the irriga- 

 tion channels. In the narrow valleys of the Nejd plateau 

 in central Arabia and on the mountain slopes of Oman 

 are found the same irrigated gardens and terraced plan- 

 tations," ' 2(i 



Mesopotamia, Persia and Central Asia, together with 

 Afghanistan and Beluchistan have, or have had in the 

 past, extensive irrigation systems.' 27 Mr. Cresswell men- 

 tions several districts west of Persia in Chinese Turkestan 

 such as Kashgar, Yarkand and Khotan where extensive 

 irrigation has been carried out. (Cf. also Semple, 359.) 

 The careful irrigation of Geok Tepe astonished the 

 Russians when they arrived there.' 28 Terraced irrigation 

 is found in the provinces of Sze Shuan and Shen-shi in 

 China, 29 " In south-west China there are two or three 

 ranges between Ch'ung-Ch'ing and Lu-chou with summits 

 about 2,000 feet above the sea, but little hills and narrow 

 valleys form the distinctive features of this country. The 

 rock is a soft sandstone and shale, often much displaced. 

 The softness of the stone makes terraced cultivation very 

 easy, and this system is carried to greater perfection here 

 than in any other part of China. Crossing one of the little 

 cols, and looking on the valleys that break away from it, 

 one is struck by the thought of the sum of human labour 

 expended to bring rugged hills into such complete sub- 

 jection, and one receives a most lively impression of the 



96 Semple, p. 567. 



27 See an exceedingly interesting and suggestive article by K. A. C. 

 Cresswell, " Fluctuations in the Population of Irrigated Countries." Man, 

 1915, 40. 



Q8 Ratzel, III.; p. 331. 



2y Semple, pp. 568-9. 



