THE JUKASSIC AGE. 



effaced the traces, by which the outlines of the land and water 

 during these successive periods have been determined. 



331. It will be seen by reference to the section (fig. 152), that 

 the series of stages from the Vosges towards Paris are still in 

 concordant superposition, being very nearly parallel and hori- 

 zontal, or if they dip it is always towards the middle of the 

 basin, as strata do when deposited at present in tranquil waters. 

 Except some occasional faults, there are no violently inclined 

 or disrupted strata either in the Anglo-Parisian basin or north of 

 the Pyrenean. 



When, however, the state of the stratification of these stages 

 on the slopes of the Alps are examined, a very different state of 

 things is encountered. There we find them broken, and thrown 

 into all inclinations, from the vertical to the horizontal ; the 

 obvious effects of the catastrophe, which in forcing up the great 

 chain of the Alps burst through the Jurassic formation, disrupting 

 its stages, and throwing them upon the declivities into all incli- 

 nations. On examining the sections of the strata as they are 

 ranged upon the slopes of the Alps, we find, notwithstanding the 

 violence to which they have been submitted, the same regular 

 succession of ten stages occurring in the same order as around the 

 Anglo-Parisian basin, where they were deposited successively, 

 and in a state of comparative tranquillity. All this indicates 

 that for long intervals of time previous to the elevation of the 

 chains of the Alps and Pyrenees, the region on which they now 

 stand was covered by the Jurassic seas, upon the bottom of which 

 the strata of the Jurassic formation were deposited, and that it 

 was long after the consolidation of these strata, that the violent 

 action of the fluid matter of the internal parts of the earth, 

 breaking the crust, forced the igneous rocks which now form the 

 Alps and Pyrenees through the disrupted Jurassic stages. 



332. Observations made upon the organic deposits of the 

 Jurassic strata fully confirm these views. The shore lines of the 

 Anglo -Parisian and other basins, those outlines marked on the 

 map by the differently tinted shadings, are characterised by those 

 shells which are deposited on the very borders of seas within the 

 play of the tides. The deposits within these are those which take 

 place in the deeper littoral regions, but those which are found 

 upon the section of the strata disrupted upon the slopes of the 

 Alps and Pyrenees, are the classes known to live only in the 

 depths of the ocean. With the exception, therefore, of certain 

 points giving coast indications, the Alps, or rather the space on 

 which they stand, were in the midst of the Jurassic ocean. 



333. During this age the island of the Yar, already mentioned, 

 was considerably increased. The land of the Vosges and the 



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