THE SURFACE OF THE GLOBE. 137 



Beneath the chalk are green sands, the lower layers of which have 

 some organic] remains. Still deeper are ferruginous sands. In many 

 countries, both these are strongly marked with sandstone layers, in 

 which are also found lignites, amber, and relics of animals. 



Under this is the vast mass of strata composing the chain of Jura 

 and the mountains which form its continuation into Swabia and Fran- 

 conia ; the main ridge of the Appenines, and a vast many beds in 

 France and England. It consists of calcareous slates, rich in fish and 

 crustaceous animals ; extensive beds of oolites, or of a granular lime- 

 stone ; marl, grey limestone, having pyrites characterised by the pre- 

 sence of ammonites ; oysters with bent valves, termed gryphaeae ; and 

 of reptiles more and more singular in construction and character. 



Extensive layers of sand and sand- stone, often bearing vegetable 

 impressions, support all these beds of Jura, and are themselves sup- 

 ported by a layer of limestone, which is so replete with numerous 

 shells and zoophytes that Werner has called it by the too common 

 name of shelly limestone, and which other sandstone strata, of the 

 sort called variegated sandstone, separate from a limestone still more 

 ancient, not less incorrectly called Alpine limestone ; because it composes 

 the high Alps of the Tyrol, but which in fact is found in our eastern 

 provinces, and throughout the whole south of Germany. 



It is in this limestone, termed shelly, that the vast masses of gyp- 

 sum and rich layers of salt are deposited; and beneath it are thin 

 layers of coppery slates, very rich in fish, and amongst which are also 

 found fresh-water reptiles. The coppery slate is supported by a red 

 sandstone of the period when those famous layers of coal were depo- 

 sited, the resource whence the present generation is supplied, and the 

 remains of the earliest vegetable productions which ornamented the 

 face of the globe. We find, from the trunks of ferns, whose impres- 

 sions they have preserved, how much these ancient forests differed 

 from the present. 



We next arrive at those transitive formations in which primaeval na- 

 ture, a nature inanimate and solely mineral, seemed still to contend 

 for empire with animated nature. Black limestone, and slates which 

 only present Crustacea and shells of species now extinct, are present- 

 ed alternately with the remains of primitive formations, and announce 

 to us the fact of our having reached the most ancient formations that 

 it has been permitted to us to discover ; those ancient foundations of 

 the actual coating of the globe, the marble and primitive slates, the 

 gneisses, and finally the granites. 



Such is the exact arrangement of the successive masses with which 

 vol. i. p 



