304 COSMOS. 



As the external configuration of continents which we have 

 already described in their horizontal expansion, exercises by 

 their variously indented littoral outlines a favourable influence 

 on climate, trade, and the progress of civilization; so likewise 

 does their internal articulation, or the vertical elevation of 

 the soil, (chains of mountains and elevated plateaux,) give rise 

 to equally important results. Whatever produces a polymor- 

 phic diversity of forms on the surface of our planetary habita- 

 tion such as mountains, lakes, grassy savannas, or even 

 deserts encircled by a band of forests- impresses some peculiar 

 character on the social condition of the inhabitants. Ridges 

 of high land covered by snow impede intercourse; but a 

 blending of low discontinued mountain chains* and tracts of 

 valleys, as we see so happily presented in the west and south 

 of Europe, tends to the multiplication of meteorological pro- 

 cesses, and the products of vegetation; and from the variety 

 manifested in different kinds of cultivation in each district, 

 even under the same degree of latitude, gives rise to wants 

 that stimulate the activity of the inhabitants. Thus the 

 awful revolutions, during which, by the action of the interior 

 on the crust of the earth, great mountain chains have been 

 elevated by the sudden upheaval of a portion of the oxidised 

 exterior of our planet, have served after the establishment of 

 repose, and on the revival of organic life, to furnish a richer and 

 more beautiful variety of individual forms, and in a great 

 measure to remove from the earth that aspect of dreary uni- 

 formity which exercises so impoverishing an influence on the 

 physical and intellectual powers of mankind. 



According to the grand views of Elie de Beaumont, we 

 must ascribe a relative age to each system of mountain 

 chains f on the supposition that their elevation must neces- 

 sarily have occurred between the period of the deposition 

 of the vertically elevated strata, and that of the horizon- 



* Humboldt, Rel. hist., t. iii. pp. 232-234. See also the able remarks 

 on the configuration of the Earth, and the position of its lines of eleva- 

 tion, in Albrechts von Koon, Grundzugen der Erd Vb'lker und Staaten- 

 tunde, Abth. i. 1837, s. 158, 270, 276. 



f Leop. von Buch, Ueber die geognostischen Systemc von Deutsdi- 

 land, in his Geogn. Brief en an Alexander von Humboldt, 1824, s. 265- 

 271 ; Elie de Beaumont, Hecherches sur les Revolutions de la Surface 

 du Globe, 1829, pp. 297-307. 



