9-253. New York, 1899.

[1230] _Ibid._, p. 282 and cartogram, p. 284.

[1231] Sir Thomas Holdich, India, p. 201. London, 1905. Imperial
Gazetteer of India, Vol. I, p. 295. Oxford, 1907.

[1232] Census of India, 1901, Ethnographic Appendices, Vol. I, p. 60, by
H. H. Risley, Calcutta, 1903. C. A. Sherring, Western Tibet and the
British Borderland, pp. 341-353. London, 1906.

[1233] B. Lavisse, _Histoire de France_, Vol. II, Part 1, p. 294. Paris,
1903.

[1234] George Adam Smith, Historical Geography of the Holy Land, pp.
383, 384, 391-400, 407, 409. New York, 1897.

[1235] Wilhelm Deecke, Italy, pp. 20, 21. London, 1904.

[1236] Francis Younghusband, The Heart of a Continent, pp. 150, 194,
199. London, 1904.

[1237] E.F. Knight, Where Three Empires Meet, pp. 12, 88, 157-159, 231.
London, 1897.

[1238] _Ibid._, pp. 173, 177.

[1239] Sir Thomas Holdich, India, map p. 85, pp. 86, 89. London, 1905.

[1240] Vambery, _Reise in Mittelasien,_ pp. 371-375. Leipzig, 1973.

[1241] C.A. Sherring, Western Tibet and the British Borderland, p. 136.
London, 1906.

[1242] O.P. Crosby, Tibet and Turkestan, pp. 112-116. New York, 1903.

[1243] Elisee Reclus, Asia, Vol. II, pp. 50-51. C.A. Sherring, Western
Tibet and the British Borderland, pp. 146-148, 152, 157, 300-303.
London, 1906.

[1244] _Ibid._, pp. 326-327.

[1245] _Ibid._, pp. 4, 61-64, 310-311.

[1246] _Bella Gallico,_ Book III, chap. I.

[1247] Strabo, Book IV, chap. VI, 1, 11.

[1248] Strabo, Book IV, chap. VI, 10.

[1249] Sir Thomas Holdich, The Indian Borderland, p. 48. London, 1909.

[1250] H.R. Mill, International Geography, p. 467. New York, 1902.

[1251] Pallas, Travels Through the Southern Provinces of Russia, Vol. I,
p. 431. London, 1812.

[1252] E.A. Freeman, Historical Geography of Europe, Vol. I, pp.
286-287. London, 1882.

CHAPTER XVI

INFLUENCES OF A MOUNTAIN ENVIRONMENT

[Sidenote: Zones of altitude.]

There are zones of latitude and zones of altitude. To every mountain
region both these pertain, resulting in a nice interplay of geographic
factors. Every mountain slope from summit to piedmont is, from the
anthropo-geographical standpoint, a complex phenomenon. When high
enough, it may show a graded series of contrasted complementary
locations, closely interdependent grouping of populations and
employments, every degree of density from congestion to vacancy, every
range of cultural development from industrialism to nomadism