GEOLOGICAL DEPOSITS OF GEE AT BRITAIN. 



119 



Sub-Medial Order, 

 (Conyleare) 



f Devonian Group 



Silurian Group 



[.Cambrian Group 



[" Conglomerate and Sandstone 

 < Corn stone and Marl 

 [_ Tilestone 



C Upper. 



Upper Ludlow Rock 

 Aymestry Limestone 

 Lower Ludlow Rock 

 J Wenlock Limestone 

 Wenlock Shale 



Lower. 



Caradoc Sandstone 

 Llandeilo Flags. 



{Slate Rocks of North Wales, 

 Cumberland, Westmoreland, 

 &c. 



STRATIFIED NON-FOSSILIFEROUS ROCKS. 



r Clay Slate 



Inferior Order, Talcose Slate 



(Conybeare) . 4 Metamorphic Group < Mica Slate 



Hornblende Slate 

 '-Gneiss 



Unstratified Rocks 



IGNEOUS ROCKS. 



f Volcanic Group 



L Plutonic Group 



( Basalt 



I 'Greenstone 

 Claystone 

 -j Trachyte 

 Porphyry 

 I Amygdaloid 

 ^Lava, &c. &c. 



C Granite 

 J Syenite 

 | Eurite 

 (^Pegmatite. 



V This Table is adopted, with slight modifications, from Mr. TENKANT'* 

 " British Fossils." 



GEOLOGICAL DEPOSITS OF GREAT BRITAIN. The student 

 should trace each separate group on a geological map of the 

 British Isles. 



To commence with the most recent, the tertiary system. 



