52 THE ORIGIN OF MOUNTAINS. [V. 



will be found an allusion to the rival theories of upheaval and 

 accumulation as applied to volcanic mountains, the discussion 

 between which we conceive to be settled in favor of the latter 

 theory by the reasonings and observations of Constant-Prevost, 

 Scrope, and Lyell. A similar view to the former applied to 

 mountain-chains like those of the Alps, Pyrenees, and Alle- 

 ghanies, which are made up of aqueous sediments, has been 

 imposed upon the world by the authority of Humboldt, Von 

 Buch, and Elie de Beaumont, with scarcely a protest. Buffon, 

 it is true, when he explained the formation of continents by 

 the slow accumulation of detritus beneath the ocean, conceived 

 that the irregular action of the water would give rise to great 

 banks or ridges of sediments, which when raised above the 

 waves must assume the form of mountains. Later, in 1832, we 

 find De Montlosier protesting against the elevation-hypothesis 

 of Von Buch, and maintaining that the great mountain-chains 

 of Europe are but the remnants of continental elevations which 

 have been cut away by denudation, and that the foldings and 

 inversions to be met with in the structure of mountains are to 

 be looked upon only as local and accidental 



In 1856, Mr. J. P. Lesley published a little volume entitled 

 Coal and its Topography, in the second part of which he has, 

 in a few brilliant and profound chapters, discussed the princi- 

 ples of topographical science with the pen of a master. He 

 there tells us that the mountain lies at the base of all topo- 

 graphical geology. Continents are but congeries of mountains, 

 or rather the latter are but fragments of continents, sep- 

 arated by valleys which represent the absence or removal of 

 mountain-land; and again, "mountains terminate 'where the 

 rocks thin out." 



The arrangement of the sedimentary strata of which moun- 

 tains are composed may be either horizontal, synclinal, anti- 

 clinal, or vertical, but from the greater action of diluvial forces 

 upon anticlinals in disturbed strata it results that great moun- 

 tain-chains are generally synclinal in their structure, beiii 

 fact but fragments of the upper portion of the earth's crust 

 lying in synclinals, and thus preserved from the destru 



