FOSSIL MAMMALIA. 27 



A very considerable portion of Germany and England is 

 composed of strata anterior to the chalk, in the hollows of 

 which the chalk reposes, just as the intermediate strata before 

 mentioned rests in its own cavities. Immediately under the chalk, 

 and indeed paitially intermingled in its lowest strata, are de- 

 positions of green sand, and ferruginous sand below it. In many 

 countries both are found condensed into l)anks of sandstone, 

 in which are seen lignites, succinum, and debris of reptiles. 



After these come the immense accumulation of strata com- 

 posing the mountain-chain of Jura, which extends into Suabia 

 and Franconia, the chief summits of the Apennines, and many 

 similar formations in England and France, 'i'liey consist in 

 calcareous schistus, abounding in fish and Crustacea, immense 

 banks of oolite, marly and pyriteous grey limestone, containing 

 ammonites, oysters with curved valves, and reptiles of more 

 extraordinary character and conformation than any of their 

 predecessors. 



These, which we shall take leave to call Jurassic strata, are 

 supported by extensive beds of sand and sandstone, in which 

 the impressions of vegetables are frequently found, and which 

 rest upon a limestone which has been termed coquillaceous, 

 from the immense quantities of shells and zoophytes with which 

 it abounds. It is separated by other strata of sandstone of the 

 variegated kind, from a limestone still more ancient, called 

 Alpine, because it composes the loftier range of the Tyrol 

 Alps ; but, in fact, it appears also continually in the east of 

 France, and the entire south of Germany. 



In the limestone called coquillaceous, are deposited consi- 

 derable accumulations of gypsum and rich beds of salt. Be- 

 low it we find slender strata of coppery schistus, with abundant 

 remains of fish, and some fresh- water reptiles. The coppery 

 schistus rests upon a red sandstone, of the same age as the pit- 

 coal, which we have before alluded to as bearing the impres- 

 sions of the earliest vegetable productions which adorned the 

 surface of the globe. 



