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Inquiries respecting the Relative Age of Mountains. 



M. Ej,iE DE Beaumont lately read to the Academy of 

 Sciences of France, a memoir, entitled Inquiries respecting some 

 of the Revolutions of the Earth's surface^ presenting different 

 examples of the coincidence xchich appears to have existed be- 

 tween the raising of the beds of certain systems of mountains, 

 and the sudden changes attested by the rapid variations of the 

 characters which are observed among certain consecutive stages 

 of the sedimentary deposites *. 



Geologists are generally agreed in thinking that the sedimen- 

 tary beds which are frequently seen in mountainous countries 

 inclined at very large angles or placed vertically, and of which 

 certain parts even occur in a reversed position, could not have 

 been formed in this position ; but that they have, on the contrary, 

 been placed in it through the eflFect of phenomena which took 

 place after the first epoch of their deposition, and which, as the 

 author remarked, must have happened at very different epochs 

 in the different systems of mountains which appear upon the 

 surface of the globe. 



Other observations have been made by geologists who have 

 carefully studied the sedimentary deposites depending upon 

 the slow and more or less tranquil action of the waters, and 

 by naturahsts who have examined the remains of animals and 

 vegetables which these deposites contain. They have gene- 

 rally remarked, that at different heights abrupt variations ma- 

 nifest themselves at once in the position of the strata, and in the 

 animal and vegetable fossils which are contained in them. 



Struck with the co-existence of these two parallel series of in- 

 termittent facts, and the analogies which seem to approximate 

 them, the author has tried to bring them into mutual relation 

 in the part of the history of the globe which is least remote from 

 the present era. 



His object has been to prove that the epochs to which several 

 of the solutions of continuity which are observed in the series 

 of sedimentary deposites correspond, have coincided with those 

 of the convulsions to which are owing the raisings and disloca- 



• This interesting memoir contains a view similar to one delivered sonic 

 years ago, hv the Professor of Natural History in Edinburgh. 



