176 GEOLOGICAL HISTORY. 



where now the coal strata extend, and much beyond their actual 

 extent. And there is no doubt that the elevation of this tract 

 into great ranges of hills is the work of a somewhat later geo- 

 logical period. 



The region of the coal strata indeed, and all the area connected 

 with it, was undoubtedly sinking continually until the comple- 

 tion of the latest of these strata. But afterwards a great change 

 took place. The whole great area of the sea-bed, in this part of the 

 globe, was displaced, in some places raised to the extent of some 

 few thousand feet, so as to constitute ridges of dry and elevated 

 land. This as applied to Yorkshire caused the production of the 

 great Penine Chain, which extends southward through Derby- 

 shire, and northward through Durham and Northumberland. 

 We have thus the distinct appearance of a part of the land of 

 Yorkshire above the Primseval Ocean. 



The augmentation of land in this diagram, as compared with the former 

 one (p. 174), is in the Penine chain of the west of Yorkshire, P. Where 

 the land sloping from this passes, at S, under the sea-level of the pe- 

 riod, L, it is worn nearly to a sloping plane. On this, and farther to 

 the east, the sea deposited the Magnesian Limestone, New Red, Lias, 

 Oolites, and Chalk. 



The life of this period is partly marine, partly freshwater, 

 partly terrestrial. Of marine life we have the following main 

 groups : 



Foraminifera. 



Polyparia 41 



Crinoidea 40 



Echinida 



Conchifera Dimyaria 32 



Conchifera Monomyaria 24 



Brachiopoda 100 



Gasteropoda 91 



