ELEVATION OF MOUNTAIN RANGESo 



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in the present volume, to give a more clear and concise account of 

 M. Elie de Beaumont's views, than by quoting Professor Sedgwick's 

 summary, in his able and truly eloquent address to the Geological 

 Society in 1831 ; after which, i shall notice some corrections which 

 M. Elie de Beaumont has since found necessary to introduce. 



" By an incredible number of well-conducted observations of his 

 own, combined with the best attested facts recorded by other ob- 

 servers, M. Elie de Beaumont has proved, that whole mountain 

 chains have been elevated at one geological period, — that great 

 physical regions have partaken of the same movement at the same 

 time, — and that these paroxysms of elevatory force, have conoe 

 into action at many successive periods. 



" Step by step, we have been advancing towards the conclusion, 

 —that different mountain chains had been elevated at several distinct 

 geological periods ; and by a long series of independent observations, 

 Humboldt, Von Buch, and other great physical geographers, had 

 proved, — that the mountain chains of Europe might be separated 

 into three or four distinct systems ; distinguished from each other (if 

 I may so express myself) by a particular physiognomy, and above 

 all, by the different angles made by the bearings of their component 

 formations, with any assumed meridian. All the subordinate parts 

 of any one system were shown to be parallel ; while the different 

 systems {mountain ranges) were inclined at various angles to each 

 other. 



" By an unlooked for and most felicitous generalization, M. Elie 

 de Beaumont has now proved, that these two great classes of facts 

 are commensurate to each other ; and that each of these great sys- 

 tems of mountain chains, marked on the map of Europe by given 

 parallel lines of direction, has also a given period of elevation, limited 

 and defined by direct geological observations." 



Professor Sedgwick then describes four of these systems of moun- 

 tain chains. " The first includes the higher elevations in eastern 

 France, of the Cote d'Or, and Mount Pilas, and a portion of the 

 Jura chain ; it may also be traced in the chain of the Erzgebirge, 

 between Bohemia and Saxony. This system or mountain chain 

 never rises into mountains of the first order, but is marked, through- 

 out, by many longitudinal ridges and furrows, ranging nearly parallel 

 to each other, in a direction about north-east and south-west. It 

 will appear that this chain has been elevated, after the deposition of 

 the oolitic series, but before that of the chalk formation, for the lower 

 secondary formations, comprising the oolites, wherever they appear, 

 are elevated in broken or contorted strata, yet they preserve a paral- 

 lelism in the general direction of the ridges. On the contrary, wher- 

 ever beds analogous to chalk or green sand occur, they are found at 

 a dead level, and expand in horizontal planes into the neighbouring 

 mountains, like the sea at the base of a lofty cliff; or if they have 

 undergone any movement, it is shown to have no relation to the bear- 



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