300 COSMOS. 



uniformity wliifli exercises so Im^ioverishhii^ an influence on 

 the physical and intellectnal powers of mankind. 



According to the grand views of EUe de Beaumont, we 

 must ascribe a relative age to each system of mountain chains* 

 on the supposition that their elevation must necessarily have 

 occurred between the period of the deposition of the vertical- 

 ly elevated strata and that of the horizontally inclined strata 

 running at the base of the mountains. The ridges of the 

 Earth's crust — elevations of strata which are of the same ge- 

 ognostic age — appear, moreover, to follow one common direc- 

 tion. The line of strike of the horizontal strata is not always 

 parallel with the axis of the chain, but intersects it, so that, 

 according to my views,! the phenomenon of elevation of the 

 strata, which is even found to be repeated in the neighboring 

 plains, must be more ancient than the elevation of the chain. 

 The main direction of the whole continent of Europe (from 

 southw^est to northeast) is opposite to that of the great fissures 

 which pass from northwest to southeast, from the mouths of 

 the Rhine and Elbe, through the Adriatic and Red Seas, and 

 through the mountain system of Putschi-Koh in Luristan, to- 

 v/ard the Persian Gulf and the Indian Ocean. This almost 

 rectangular intersection of geodesic lines exercises an import- 

 ant influence on the commercial relations of Europe, Asia, 

 and the northwest of Africa, and on the progress of civilization 

 on the formerly more flourishing shores of the Mediterranean .J 



Since grand and lofty mountain chains so strongly excite 

 our imagination by the evidence they aflbrd of great terres- 

 trial revolutions, and when considered as the boundaries of 

 climates, as lines of separation for waters, or as the site of a 

 difierent form of vegetation, it is the more necessary to de- 

 monstrate, by a correct numerical estimation of their volume, 

 how small is the quantity of their elevated mass when com- 

 pared with the area of the adjacent continents. The mass 

 of the Pyrenees, for instance, the mean elevation of whose 

 summits, and the areal quantity of whose base have been as- 

 certained by accurate measurements, would, if scattered over 



* Leop. von Bach, Ueher die GeognostiscTien Systeme von Deutscklantl, 

 in his Geogn. Briefcn an Alexander von Humboldt, 1824, s. 2G5-271 

 Elie de Beaumont, Recherches sur les Rivolulions de la Surface du Globe, 

 18?9, p. 297-307. 



+ Humboldt, Asie Centrale, t. i., p. 277-283. See, also, my Essai 

 $ur le Gisement des Roches, 1822, p. 57, and Relat. Hist., t. iii., p. 

 244-250. 



t AsU Centrale, t. i., p. 284. 286 The Adriatic Sea likewise fuHowg 

 8 direction IVoni S.E. to N.W. 



