CORNISH POST-TERTIARY GEOLOGY. 21 



about high-water mark. It is possible that this may be a relic of a 

 raised beach, destroyed at a higher level. 



Between Pornanvon and Pol Pry, near the latter, the following 

 section was shown in the cliff : 



Large granite boulders in soil 



Yellowish-brown, coarse granitic debris (Growan) with large 



angular fragments 15ft. 



As above, with great angular boulders, and small fragments of 

 schorlaceous and porphyritic granite. The matrix becomes 

 darker in the lower part, and for 5 feet upward from its base, 



exhibits an appearance resembling false bedding 2oft. 



Granite boulders, round and subangular, with a few pebbles of 

 dark bluish-grey slate, resting upon decomposing granite, at 

 from 10 to 20 feet above high-water mark 2ft. to 5ft. 



(Fig. 13.) Pornanvon Cove. The cliffs near the mouth of the 

 stream give the following section : 



Head, of angular fragments of granite, some of great size, in 



coarse granitic c^e'Sri* (Growan) 20ft. 



Large granite boulders, smooth and well rounded, lying irregu- 

 larly on granite which in one place separates the bed altogether 5ft. to 15ft. 



Fig. 13. Poknanvon. 1 inch = 32 feet. 



The base of the boulder bed is from 5 to 15 feet above high-water 

 mark ; occasional smaller pebbles of slate and quartz occur in it. 

 In Priest Cove the following cliff section was obtained : 



Head, of light-brown loam, with angular slate, and, occasionally, 

 granitic fragments, becoming darker in colour, and containing 

 fewer stones for from 5 to 10 feet from its base 10ft. to 15ft. 



Blackish and brown coarse earthy sand 6in. to lit. 



Gravel, chiefly composed of pebbles of altered slate, greenstone, 



quartz, and, occasionally, flint 3in. to 2ft. 



At base 5 to 10 feet above high- water mark. 



