164 



STRATIGRAPHICAL GEOLOGY 



total thickness of the Valentian Series is much less than it is 

 in Wales. 



In the southern districts (Usk, May Hill, Woolhope, and 

 Malvern) the group consists of the May Hill sandstone and the 

 Woolhope shales. The former is about 1000 feet thick, and 

 consists of (1) a lower set of sandstones and conglomerates of grey 

 and purple colours about 600 feet thick, and yielding the usual 

 fossils, together with Ctenodonta Eastnori and Linyula crumena ; 

 (2) an upper set of grey laminated sandstones and shales from 320 

 to 500 feet thick with Pentamerus lens, P. undatus, etc., the 

 highest beds being shales which are doubtless equivalent to the 



W.byS. 



High Wood 



rtr,HiIl EbyN _ 



F * \ \ 



\ \ \ ! C 



^^^s^i. 



\V^rc.h\*\ % Areh. \Tr 

 \ \ 2 vyS. v F \ 



88 \\ y' 2 ^ 



...,, -!PP/< 

 WSWL,TS MS 2 



Fig. 51. SECTION THROUGH HIOH WOOD NEAR WEST MALVERN (Pl'OfesSOr (irOOlll). 



(Scale 6 inches to 1 mile.) 



Tr. Trias. 



WS. Wenlock shale. 

 WL. Woolhope limestone. 

 WS. Woolhope shale. 



BS. Black shales (Cambrian). 

 Arch. Pre-Cambriau. 

 PP. Faults. 



Tarannon shales. The conglomerates rest unconformably upon tlie 

 Cambrian shales where these are exposed, but elsewhere they are 

 faulted against the Archa-an rocks. The Woolhope shales are not 

 more than 200 feet thick, consisting of green and purple shales 

 with thin layers of limestone. 



In Shropshire the group consists of the following members : 



Purple shales ( Tarannon shale) . 



Pentamerus limestone 



Basement grits and conglomerates . 



200 to 400 feet. 



30 to 40 ,, 



to 120 , 



The basement beds rest unconformably on Ordovician, Cambrian, 

 and Longmyndian in different parts of the. area, varying greatly in 

 thickness, and i:i places thinning out altogether so as to leave the 

 overlying limestone in contact with the older rocks. Thus the 

 Pentamerus limestone is really a sandstone rendered calcareous by 

 the quantity of included fossil shells. The commonest fossils are 



