IOC 



THE STORY OF THE EARTH. 



change takes place. The carboniferous limestone 



S of numerous alternations of limestones 



Fig. iv— Section showing the strata on the east of the Pennine 



chain. 



with Shales, which are well exposed in the dales 

 Of Yorkshire, where they are rut through by the 

 rivers draining eastward into the North - 

 Above the limestone group, which is known as 

 the Scar Limestone or Mountain Limestone, there 

 i. a superimposed series termed the Yoredale 

 beds, which are well represented in Northumber- 

 land, Yorkshire and Lancashire, and are thickest 

 on the west side of the Pennine chain. These 

 bed- are partly sandstone, termed Yoredale grit ; 



but mainly shales, with impure limestone; so that 



they form', essentially, an upper division of the 



Carboniferous Lime-tone in the North of Eng- 

 land. In Derbyshire and Flint the carboniferous 



limestone attains an immense thickness. And 

 then southward, m the W est of England and 

 South Wales, it IS reduced to 1000 or 2000 feet, 

 with a capping of Upper Limestone Shale, which 



represents the Yofedale beds. 



Where the limestone is well developed, whether 

 in the west of Yorkshire or Derbyshire or Bristol, 



tnic Origin is Usually evident. It is formed 

 ID some places Of the remains of Lncrmites, m 



others oi Corals, occasionally of Brachiopod 



,1s, while there are a tew loeahtie lally 



U) the Bristol area, where the limestone is organic 



