STRUCTURE OF ENGLAND AND WALES. 



25 



W 



North Sea., 



Lincolnshire "Wolds 



Lincoln . 



Derbyshire Coal-field , 



N. Staffordshire Coal-field... 10 





North Wales Coal-field 



Pi ^ 



-HE 



Vale of Clwyd 



log a 



Snowdon 



Caernarvon Bay 



