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CHAPTER XXII. 



ON THE ELEVATION OF MOUNTAINS AND CONTINENTS. 



The Elevation of the Beds of Granite and Slate in England proved by the Author, 

 in 1823, to have taken place at a much earlier Epoch, than the Elevation of the 

 Granite of Mont Blanc. — The Facts on which this conclusion was founded de- 

 scribed and explained. — Application of similar Conclusions to the other Moun- 

 tain Ranges by M. Elie de Beaumont.— The Elevation of Rocks of Granite and 

 Slate, proved to have taken place by a distinct Operation from that which up- 

 heaved Continents from the Ocean, and at a different Epoch.— Elevation of the 

 Mountains and Table Land in Central Asia. — Depression of the Surface round 

 the Caspian Sea. — Instances of the Elevation and Submergence of the Earth's 

 Surface in various Parts of the Globe. 



That granite, or some modification of granite, forms the founda- 

 tion rock of the present continents, is admitted by geologists. It is 

 also ascertained, that specimens of granite, gneiss, and mica-slate, 

 from the most distant parts of the globe, appear to be identical. It 

 is, therefore, probable that the crust of granite which environs the 

 globe, was all formed or consolidated at the same epoch, though lo- 

 cal protrusions of granite have taken place at much later epochs. 



If granite be the lowest and most extensive formation of known 

 rocks, yet, in many countries, it is raised in immense ridges, forming 

 the basis of mountain ranges : sometimes the beds of granite are 

 nearly vertical, and constitute the summit as well as the central base 

 of mountains. An enquiry suggests itself ; was the elevation of these 

 mountain ranges cotemporaneous in different countries ? The fol- 

 lowers of Werner maintained, that granite mountains were crystalline 

 masses, precipitated in a universal ocean impregnated with mineral 

 matter ; and that their elevation was coeval with their origin. In the 

 year 1819, M. Daubuisson, who was regarded by the French as an 

 oracle in Geognosie, published his Traite de Geognosie, in which, 

 foHowtng the steps of Werner on most points, he asserted, that the 

 granite of the Alps attained its present elevation soon after the epoch 

 of its formation. In the years 1820, 1821, and 1822, 1 had fre- 

 quent opportunities of ascertaining the error of this opinion ; and 

 that the beds of granite were not elevated, till after the deposition of 

 the calcareous beds that rest upon them. I farther ascertained, that 

 many of these calcareous beds were identical with the upper secon- 

 dary strata in England ; hence it followed, that the granite beds in 

 the Alps were not elevated till a late geological epoch, after the de- 

 position of the oolites and chalk. This discovery I published in 

 1823, in my Travels in the Tarentaise, vol. ii. pp. 17, 18; and I 

 there distinctly stated, that the elevation of the granite of the Alps^ 

 was more recent, than the elevation of the beds of granite and slate 

 in England. Neither the importance of the discovery, nor its now 



