262 Elie de Beaumont's Researches on same of 



quillity in which we live will not be disturbed in its turn by 

 the appearance of a new system of mountains, the effect of a 

 new dislocation of the land we inhabit, and of which earth- 

 quakes teach us the foundations are not immovable. 



The independence of successive sedimentary formations is 

 the most important result obtained from the study of the su- 

 perficial beds of our globe ; and one of the principal objects 

 of my researches has been to show, that this great fact is a 

 consequence, and even a proof, of the independence of moun- 

 tain-systems having different directions. 



The fact of a general uniformity in the direction of all beds 

 upheaved at the same epoch, and consequently in the crests 

 formed by these beds, is perhaps as important in the study 

 of mountains, as the independence of successive formations is 

 in the study of superimposed beds. The sudden change of 

 direction in passing from one group to another has permitted 

 the division of European chains into a certain number of 

 distinct systems, which penetrate, and sometimes cross each 

 other without becoming confounded. I have recognised from 

 various examples, of which the number now amounts to twelve, 

 that thei-e is a coincidence between the sudden changes esta- 

 blished by the lines of demarcation observable in certain con- 

 secutive stages of the sedimentary rocks, and the elevation of 

 the beds of the same number of mountain-systems. 



Pursuing the subject as far as my means of observation and 

 induction will permit, it has appeared to me, that the different 

 systems, at least those which are at the same time the most 

 striking and recent, are composed of a certain number of 

 small chains, ranged parallel to the semicircumference of the 

 surface of the globe, and occupying a zone of much greater 

 length than breadth ; and of which the length embraces a 

 considerable fraction of one of the great circles of the ter- 

 restrial sphere. It may be observed in support of the hy- 

 pothesis of each of these mountain-systems being the product 

 of a single epoch of dislocation, that it is easier geometrically 

 to conceive the manner in which the solid crust of the globe 

 may be elevated into ridges along a considerable portion of 

 one of its great circles, than that a similar effect may have been 

 produced in a more restricted space. 



However well established it may be by facts, the assem- 

 blage of which constitutes positive geology, that the surface 

 of the globe has presented a long series of tranquil periods, " 

 each separated from that which followed it by a sudden and 

 violent convulsion, in which a portion of the earth's crust was 

 dislocated, — that, in a word, this surface was ridged at intervals 



in 



