MOUNT ABU 



5565 



MOUNTAIN 



Mountain. Diagram illustrating relative heignts of the world's chiet mountains 



Mount Abu. Culminating 

 point of the Aravalli Hills, India. 

 It is in Rajputana, 68 m. W. of 

 Udaipur. The sanatorium, known 

 by the same name as the mountain 

 on which it stands, is 3,945 ft. in 

 elevation. There are two fine 

 temples built by the Jains. Of 

 white marble, they date from the 

 12th and 13th centuries, and are 

 held to be the finest extant speci- 

 mens of Indian architecture. The 

 altitude of Mt. Abu is 5.650 ft. 



Mountain. Term used some- 

 what loosely to describe an elevated 

 portion of the earth's crust. Alti- 

 tude alone does not justify the ap- 

 plication of the term to high 

 ground, for an isolated elevation of 

 less than 1,000 ft. frequently re- 

 ceives the designation, although it 

 is usual to describe a ridge of this 

 moderate elevation by the term hills, 

 while high ground between 1,000 

 and 5,000 ft. is called hills in one 

 place and mountains in another. 



The term mountain does not 

 necessarily signify steep slopes in 

 two directions, for the scarped edge 

 of the central plateau of France 

 is known as the Cevennes Mts. The 

 term is generally used to express 

 the dominant aspect of the high 

 ground over the immediate locality. 



The earth's crust is for ever un- 



Mountain. Diagram* illustrating 



bow lateral pressure towards a fixed 



point produces folding 



dergoing changes by warping, 

 fracture, and weathering, and this 

 complex of activities, slow in pro- 

 cess but cumulative in effect, pro- 

 duces the variations in elevation to 

 which mountains are due. In the 

 simplest cases mountains are due to 

 actual building, for volcanic cones, 

 as Fuji, Egmont, and Vesuvius, are 

 the product of volcanic outbursts. 

 Laccolithic eruptions produce such 

 domes as the Henry Mts. of Utah 

 without superficial outflowing of 

 lava. These are the mountains of 

 accumulation. 



During geological times the earth 

 has decreased in volume, and its 

 crust has adjusted itself to the 

 changing conditions and has thus 

 produced crinkles, the result of 

 the tangential warping strains pro- 

 duced continuously during the ad- 

 justment. The most recent crinkles 

 are the great mountain ranges of 

 the world as we now know them ; 

 here the strata of the crust are 

 contorted, simply as great up and 

 down folds, or complexly with 

 folds, fractures, and the overthrust 

 of one mass of rock over another. 



The agencies of weathering 

 steadily strive to reduce the earth's 

 surface to a dead level, with the con- 

 sequence that many mountain 

 forms, such as the Cumbrian group 

 in the Lake District of England, are 

 merely the worn-down stumps of 

 much mightier peaks. 



The greater number of the fold 

 mountains of the world are geo- 

 logically young mountains belong- 

 ing to the Tertiary Age ; the great 

 E.-W. line, Himalayas, Caucasus, 

 Alps, Atlas, the two N.-S. lines 



bordering the Pacific Ocean, the 

 Rockies, Andes on it* E. margin, 

 and the Japanese, E. Indian, and 

 New Zealand Mt. on it* W., all 

 belong to this period. The moun- 

 tains of Africa, Drakensberg, 

 Abyssinian Highland's <!<. , make a 

 third N.-S. line, but this belongs 

 to an earlier period, to the ancient 

 continent of Gondwanaland. 



In general, the climate and 

 natural vegetation of a mountain 

 side follow the same sequence as 

 would be observed in travelling 

 over the surface polewards from 

 the mountain foot. Yet this ana- 

 logy only applies approximately. 

 In the case of climate, although the 

 temperature falls regularly as the 

 mountain is ascended, yet the sea- 

 sonal range of temperature hardly 

 changes with elevation, while the 

 diurnal range of temperature at 

 high altitudes differs considerably 

 from that at high latitudes. 



In their control of human activi- 

 ties mountains have had different 

 effects in relation to the rapidity 

 with which man habitually travels. 

 Under modern conditions the Alps, 

 Rockies, Andes, and Himalaya? are 

 a barrier to human movement ; in 

 historic times the Alleghenies con- 

 trolled the routes by which the 

 pioneers opened up the fertile 

 centre of N. America ; but in 

 earlier times the Carpathians and 

 the Alps in Central Europe, like the 

 Downs of S. England, provided 

 ruutes along their pastoral levels 

 which were followed by early man, 

 who was averse from crossing the 

 heavily forested low lands. 



In the more settled areas of the 

 world mountainous districts are 

 frequently the homes of backward 

 peoples ; some of these have settled 

 in mountainous valleys in isolation ; 

 others, like the Montenegrins, have 

 taken to the mountains as a refuge 

 from the oppressor; others again, 

 like the Transylvanian Rumanians 

 and the Slovaks, have been driven 

 to the heights by their foes. Whilo 

 the Andorrans are isolated in their 

 Pyrenean fastness, the Basques 

 and the Swiss have gained by their 

 location. Mountains frequently 

 serve as political boundaries, the 

 Andes, Caucasus, Himalayas all 

 serve this purpose ; but they only 

 make good frontiers when they lie 

 in sparsely peopled regions. See 

 Alps ; Earth ; Geology ; Glacier : 

 Himalayas; Rocks. B. c. Wain* 



Bibliography. Earth Sculpture, J. 

 Oeikie, 1 898 ; Physical Geography, 

 VV. M. Davis, 1902 ; The Face of the 

 Earth, vol. 1, E. Suess, 1904; A 

 Text -hook of Geology, P. Lake and 

 R. H. Rastall, 2nd ed. 1913 ; Moun- 

 tains, Their Origin, Growth, and 

 Decay, J. Geikie, 1913; The Scienti- 

 fic Study of Scenery, J. E. Marr, 

 5th ed. 1918. 



