310 



PEOP. A. H. COX A>"D MP. A. K. WELLS ON THE [vol. lxxvi, 



complicated ; faulting has evidently been in operation along the 

 same lines on various occasions, with the result that the same 

 fault appears now earlier; now later, than the intrusive rocks. 

 Accordingly, a description of each of the main strike-faults will 

 be D-iven. 



V-l 



Cbis 



^ 



(i) The Derwas Fault. — This fault was first mentioned by 

 Mr. Lake & Prof. Eeynolds as bringing Dolgelley Beds against. 

 Ffestiniog Beds, and acting as a normal fault with a downthrow to 

 the south-east. 1 Those authors were uncertain as to whether the 

 fault actually shifted the neighbouring diabase-intrusion, but they 



, J. G.S. vol. Hi (1896) p. 513. 



