CORNISH POST-TERTIARY GEOLOGY. 



23 



The cliffs from a point west of Gwythian to Godrevy Island 

 exhibit a very fine example of a raised beach, at base from 5 to 8 

 feet above high-water mark. 



In one spot, west of Gwythian, the low cliff consists of: 



Blown sand 2ft. Oin. 



Brown sand 5ft. Oin. 



Gravel of grit, slate, quartz, and a few flint pebbles near the base, 

 at about 5 feet above high- water mark ; coarse black consoli- 

 dated sand, containing pebbles, fills up the inequalities in the 

 subjacent grey slate platform 2ft. Oin. 



(Fig. 15.) At nearly three-quarters of a mile to the south of 

 Godrevy Island, I obtained the following section : 



1. Head, of light-brown and grey loam, with angular fragments. 



stained blackish at the base 15ft. 



2. Brown and drab iron-stained sand, with bands of pebbles in places 10ft. to 15ft. 



3. Pebbles of quartz and slate, of various sizes, with subangular 



fragments of slate in coarse sand, consolidated near the base 

 in which a large boulder was noticed. Base of pebbles, 5 feet 

 above high-water mark 1ft. to 5ft. 



Fig. 15. Godrevy Cliffs looking toward Gwythian. 

 Vertical height represented in foreground = 34 feet. 



Near the above the old consolidated pebble beach forms the roof 

 of cavernous hollows in the slates in two places. Where the con- 



