MEMOIRS 



OP THE 



GEOLOGIICAL SURYEY 



OP 



THE UNITED KINGDOM. 



ILLUSTEATIVE OP 



BRITISH ORGANIC REMAINS, 



DECADE XL 



TRILOBITES, 



(chiefly SILURIAN.) 



PtBLISHED BY OEDER OP THE LORDS COMMISSIONEBS OP HER MAJESTY'S TREASURY. 



LONDON: 



FEINTED rOE HER MAJESTY'S STATIONERY OFEICE : 

 PUBLISHED BY 



LONGMAN, GKEEN, LONGMAN, EGBERTS, & GREEN ; 



AND BY 



EDWARD STANFORD, 6, Charing Cross, S.W. 



1864. 



Price 2s. 6d. 



