CHANGES OF LEVEL. 247 



Black Forest and that of the anthracite schists (the Carbonife- 

 rous island), and that the lowering of the ground increased in 

 the direction from the Jura towards the existing Alps, so that it 

 attained its maximum on the southern side. Hence, when the 

 land was upheaved, shallow water and firm land were produced 

 along the Jura earlier than along the Alps. A marine lagoon 

 remained along the Alps during the period of transition from 

 the Jurassic to the Cretaceous epoch, and even to the Eocene 

 period, the Jura being all the while dry. It is very remarkable 

 that the Helvetic Miocene sea never invaded the region of the 

 Alps, although it left deposits in the district of the Jura, as for 

 instance at La Chaux de Fonds and at Locle. Therefore the 

 land in the Alps must have been more elevated than in the Jura 

 after the formation of the Flysch, and this upheaval continued 

 to the time when the Helvetic sea covered the low grounds, and 

 the Eocene Alpine formations rose above the sea, and the Jurassic 

 Eocene was under water ; and yet the Alpine Eocene strata had 

 been produced in the sea and the Jurassic Eocene owed its origin 

 to fresh water. These circumstances show us at the same time 

 that as the Jura and the Alps present such different character- 

 istics, the upheaval of the land mest furnish the best explanation 

 of the phenomena under consideration. 



To ascertain the periods during which upheavals or depressions 

 took place in Swiss mountain-masses, we must consult the rela- 

 tive positions of the strata. Near Utznach the lignites, or 

 paper-coals, lie horizontally upon the perpendicularly raised 

 sandstone rocks (see p. 152, fig. 329) ; so that it is clear that the 

 upheaval of the Miocene took place before the deposition of the 

 lignites. Where we meet with a deposit of this kind uncon- 

 formable with the strata below it, we may always conclude that 

 in the interval between the two formations a- great change had 

 taken place. When strata of different ages follow one another 

 uniformly no partial or local upheaval can have occurred, al- 

 though there may have been a general upheaval. When of two 

 superimposed strata, the lower contains freshwater animals, and 

 the upper marine animals, we may conclude that at the time ot 

 the formation of the freshwater bed the land stood above the 

 level of the sea, and that during the formation of the marine 



