CHAP. xvi. OSCILLATIONS OF LEYEL. 335 



hundreds of miles apart ; so that, instead of the land subsiding 

 five feet in a hundred years, as at the North Cape, it becomes 

 less than the same number of inches at Stockholm, and 

 farther south the land is stationary, or, if not, seems rather 

 to be descending than ascending.* 



To cite an example of high geological antiquity, M. Hebert 

 has demonstrated that, during the oolitic and cretaceous 

 periods, similar inequalities in the vertical movements of 

 the earth's crust took place in Switzerland and France. By 

 his own observations and those of M. Lory he has proved 

 that the area of the Alps was rising and emerging from 

 beneath the ocean towards the close of the oolitic epoch, and 

 was above water at the commencement of the cretaceous era ; 

 while, on the other hand, the area of the Jura, about one hun 

 dred miles to the north, was slowly sinking at the close of the 

 oolitic period, and had become submerged at the commence 

 ment of the cretaceous. Yet these oscillations of level were 

 accomplished without any perceptible derangement in the 

 strata, which remained all the while horizontal, so that the 

 lower cretaceous or neocomian beds were deposited conform 

 ably on the oolitic.f 



Taking for granted then that the depression was more 

 rapid in the more elevated region, the great rivers would lose, 

 century after century, some portion of their velocity or 

 carrying power, and would leave behind them on their 

 alluvial plains more and more of the moraine-mud with 

 which they were charged, till at length, in the course of 

 thousands or some tens of thousands of years, a large part of 

 the main valleys would begin to resemble the plains of Egypt, 

 where nothing but mud is deposited during the flood season. 

 The thickness of loam containing shells of land and am- 



* Principles of Geology, chap. xxx. de France, 2 series, torn. xvi. p. 596, 

 9th ed. p. 519 et seq. 1859. 



f Bulletin de la Societe Greologique 



