INTEODUCTION. 



Primaey Period. (Paleozoic Series, Phillips.) 



(Permian or Magne- f MagnesianLimestone. 

 sian Limestone S Lower Red Sand- 

 Group. ^ stone. 



Medial Order. 

 {Cotiybeare.) 



{r Coal Measures. 

 Carboniferous Group. < Millstone Grit. 

 I Mountain Limestone 



Submedial Order. 

 (^Conybeare.) 



(Conglomerate and 

 Sandstone. Comstone 

 and Marl. Tilestone. 



lurian Group. 



Upper Ludlow Rock. 

 Aymestry Limestone. 

 Lower Ludlow Rock. 

 Wenlock Limestone. 

 Wenlock Shale. 



Lower. 

 Caradoc Sandstone. 

 Llandeilo Flags. 



Cambrian Group. 



Under this head are now arranged the older slate rocks of North 

 Wales, Cumberland, Westmoreland, &c. {See Professor Sedgwick's 

 Memoirs.) 



Stratified Non-fossili- 



ferons. Metamorphic 



Rocks. {LyelL) 



Inferior Order. 

 {Conybeare) 



r Clay Slate. 



Talcose Slate. 

 ■t Mica Slate. 

 . Hornblende Slate. 

 L Gneiss. 



