THE PRE-ADAMITE EARTH. 



minated the fifth period raised the bottoms of the Breton and 

 Yosgian Straits, so as to separate completely the Anglo-Parisian 

 from the Pyrenean and Mediterranean basins, and thus to connect 

 Brittany on the one side, and the Yosgian continent on the other, 

 by two isthmuses. 



369. The Mediterranean basin extended across the Tyrol, and 

 into Switzerland, as faras Soleure, and probably even to the 

 Crimea. But the greatest change produced by this convulsion 

 was the subsidence of the great Russian continent, which had 

 continued above the sea since the close of the palaeozoic age, and 

 the consequent extension of the seas of this sixth period over all 

 Russia, from the 48th degree of latitude to the Frozen Ocean. It 

 appears also from the organic remains of Mollusca and Radiata, 

 that these seas extended on the south, without interruption, to 

 the 9th degree of latitude, thus covering the entire extent of 

 Asia, from the province of Cutch to the polar circle. 



SEVENTH JURASSIC PERIOD. 



370. The deposits of this period, called by D'Orbigny the 

 Oxfordian stage, correspond with the upper strata of the Oxford 

 clay, or the dark-blue clay of Oxfordshire and the Midland 

 counties, the thickness of which in England, according to Lyell, 

 is sometimes 500 feet. In the south-west of France, and in the 

 Alps, it measures from 320 to 500 feet. 



371. In the following table we give a synopsis of the generic 

 forms of this period, excepting the Annulata : 



Synopsis of the Animal Kingdom (exclusive of the Annulata) during the 

 Seventh Jurassic Period. 



S3 



