290 



Messrs. Buckland's and Conybeare's Observations on the 



Porcelain limestone 

 Dark grey limestone 

 jy ,. Ball limestone in clay matrix 



,"" _, _, < Small blue beds 



stone shale. 



Mountain . 

 limestone, a 



Limestone. 



Greyish-blue limestone with purple joints 



White limestone 



Iron ore and marl, from 3 fath. to 



Great white- cliff bed of limestone 



Yellow clay limestone 



Great blue limestone, oolitic to the 



N.W. of Coleford, with clay 

 Sparry limestone oolitic near St. Bri- \ 



avels, and slightly so near Coleford J 

 Brownish-red limestone, with iron ore . 

 Swan-pool, or Cherry-orchard limestone 



} 



::{ 



- stone shale. I Straw-coloured sandstone 



FaUi. Ft. In. 

 3 



2 

 4 

 3 



17 3 



3 

 8 



40 



7 3 



4 



5 



4 



12 3 



2 3 



4 



117 3 



r 



Old red 

 sandstone 



J 



I 



Upper gritty bed of the great red formation 

 Great plum. pudding stone 

 ' Best section be-' 

 tween Ross and 

 Perriston-hill on 

 the road to Led- 

 . bury. 



Great red 

 sandstone ' 



20 

 10 



from 630 to 



from 600 to 800 



830 



Transition f 

 limestone. 1 



Limestone as seen cropping out from beneath the great red sand- 

 stone at Longhope and Huntley. 



Chapter IV.— ON THE OVERLYING STRATA. 



1. Newer red sandstone. 



Conglomerate, red sandstone, and red marl, together constitute the forma- 

 tion to which the terms red ground and red marl have been applied, and 

 which we have called the newer red sandstone. The average total thickness 

 of this formation in the south-western coal-district, is about 200 feet, which 

 is not much more than one fourth of the thickness, which it is known to at- 

 tain in the north-eastern parts of England. 



The lowest member of this formation is : 



