CAKBONIFEROl 99 



terrestrial and lacustrine conditions of the old red 

 dstone period. As the Calciferous Sandstone 

 . southward, it becomes represented, 

 first by the Tuediail beds of Northumberland and 

 Durham, which arc alternations of sandstones, 

 tnd impure limestones. There is no Old 

 Red Sandstone below the Carboniferous rocks in 

 the North of E igland, and from the Cheviot lake 

 • he ( )ld Red Sandstone is doubt- 

 ful! , ed. In the South W al field, 

 and the lid, and the country of the 

 Mendip Hills, the 400 or 500 feet - f 1 »wer Lime- 

 th the bone bed at or about the 

 : limestone 



1 with fish remains. 



tie life of this 



. that ol niferous >ne. 



1 4 the carboniferous rocks, 



I imest 



- in the Scot > with s md- 



md a thin 



led lijnest >ne. grouped 



1 the lower li;:. 1 »al 



upper I: - rhe mid- 



n, IS about 600 feet thick ; 

 and includes md shales 



. now highly inclined, 

 which grew they are found, and each is 



more than one foot thick. Tic- not 



entir sent from the upper limestone 



hat the tentative of the Carboniferous 



Limestone i 5 md is important, as indicating 



tern lit ions which are not quite sharply 



marked off from tho>e of the Calciferous Sand- 

 stone be' 



Travelling southward a remarkable physical 



