204 W. A. E. Ussher — Post-Tertiary Geology of Cornwall 



16. Gwythian and Godrevy. 



a. Near the southern end of Black Cliffs the slates are capped by 

 a Head of brown clay with angular stones, and a few quartz pebbles 

 at its base. 



o. South of Ceres Kock, greenish grey slates are capped by a Head 

 of greenish grey clay, probably resulting from their decomposition. 



c. West of Gwythian ; cliff-section — 



-jii^iSiiMMiiM' 



Fig. 3. — Near Gwythian. Vertical scale 1 inch =12 feet. 



1. Blown sand 2ft. Oin. 



2. Brownish loam with angular slate fragments 1ft. Oin. 



3. Agglomerate of angular slate and quartz stones in a con- 



solidated matrix of small angular pieces of slate 3ft. Oin. 



4. Fine brownish sand, consolidated in places, containing a 



few pebbles 2ft. Oin. 



5. Three beds of pebbles and subangular stones of slate and 



quartz, with occasional pieces of flint in the lower bed. 



The beds are 4in., 1ft., and 2ft. in thickness, respectively 3ft. 4in. 



d. Near the above, the Head consists of grey loam with angular 

 slate stones of small and average size. The pebble deposits occur in 

 two layers, separated by a seam of brown sand. The base of the 

 gravel is about 5ft. above high water. 



The following observations of the Cliffs of Godrevy commence at 

 a point about three-quarters of a mile to the south of Godrevy Island. 



e. The section, partially obscured by sandy debris, consists of — 



Head, yellowish and grey loam with small angular stones, and 



occasional large angular quartz fragments, resting unevenly 10ft. to 20ft 



upon — fine olive brown sand 5ft. 



Coarse grey sand with pebbles and subangxdar fragments of 

 slate and quartz, the former sometimes large 5ft. 



Consolidated coarse blackish sand with small pebbles and 



subangular fragments, and a few large pebbles variable. 



At base 5 to 8 feet above high water. 



/. The pebble band is stained blackish, it is from 6 inches to 1 ft. 

 thick, and about 6 feet above high water. At this point angular and 

 subangular fragments, some lai-ge, are associated with the pebbles in 

 a coarse impure sand matrix. 



g. Two beds of coarse blackish and reddish-brown consolidated 

 sand, containing pebbles, etc., of slate and quartz, 3 feet in maximum 

 thickness, and 6 feet above high water at their base, are capped by 



