146 



ME. J. B. SCEIVENOK ON THE 



[May 1903, 



of the St. Agnes elvan, which, as a matter of fact, continues on its 

 course apparently unbroken. Now, at St. Agnes, the elvan is dipping 

 northward at an angle which becomes steeper at Y/heal Prudence, 

 and at Hanover Cove is within a few degrees of the vertical ; not, 

 as figured by Conybeare, remaining the same as at St. Agnes. The 

 elvan is again exposed in the new railway-cutting in Perran Coombe, 



where it is seen to 

 be dipping south- 

 ward at an angle 

 of 30° ; therefore, 

 at a point not far 

 east of Hanover 

 Cove, that is, at a 

 point where the 

 north - and - south 

 fault probably cuts 

 it, it must be ver- 

 tical. Again, since 

 the surface of the 

 main body of the 

 granite mentioned 

 by Capt. Pill must 

 be at least 300 feet 

 below the top of 

 the Cligga expo- 

 sure from which it 

 is severed, as can 

 be seen from the 

 contours, it is im- 

 probable that any 

 appreciable hori- 

 zontal motion has 

 complicated the dis- 

 location. Conse- 

 quently, although 

 the elvan may have 

 been as fully affect- 

 ed by the fault as 

 the granite, it need 

 not necessarily 

 have been thrown 

 out of its course. 



Prom this it 

 follows that the 

 northern part of the granite-outcrop must be taken as an isolated 

 portion of the main mass, the southern as a tongue protruding out 

 from it into the killas ; and, moreover, it is possible, by observing the 

 form of the divisional planes, to see where this tongue commences. 



Por a little more than halfway from the northern extremity of 

 the section, these divisional planes are straight, and dip northward 

 at an angle of about 60°. They then turn over and form an anti- 





