Ch. VII.] THE GRANITIC AND SCHISTOSE ROCKS. 



129 



relation of the granite and slate may be seen in the following 

 figure : 



Fig. 9. 



Junction of Granite and Slate at Cape Comtvall. 

 (Cli ft' Section.) 



In several spots, at the places now referred to, the lines of 

 structure are distinctly and regularly continued through both 

 the granite and the slate ; but it must be also understood, 

 that in adjacent spots this continuation cannot be seen, the 

 corresponding lines not being in the same direction, or alto- 

 gether wanting in one of the rocks : it is, however, to be 

 borne in mind, that the individual beds of both the granite 

 and the slate exhibit precisely the same appearances. 



This disposition of the primary slates at their junction with 

 the granite appears to indicate that the latter was, at one 

 time, completely enveloped at the surface by the former. Be 

 this, however, as it may, we now find the granite, at various 

 points, protruding through the slates, and generally occupying 

 the most elevated positions. These masses sometimes are 

 arranged in nearly circular forms of various extent, from 

 several leagues to a few hundred feet in diameter ; at other 

 times they are elongated into considerable ridges, forming 

 what has been termed anticlinal axes, on account of the 

 strata dipping from them on either side, like the roof of a 

 house. The Ocrynian ridge, extending from Dartmoor to 

 the Land's End, has been regarded as such an anticlinal 

 axis : in a general point of view this is correct, but when 

 each of the insulated masses of granite are examined, they 

 will be found more or less concentrically enveloped by the 

 adjacent slate ; and not only so, but, if lines be drawn through 



