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



of contorted slate (believed by Mr. "Wbitley to have been 



pressed into the bed by ice) 



Red and white siliceous sand, of quartz grains partially rounded. 

 Boulders of blue grit, granite, quartz, vesicular trap (as at 



St. Minver). 

 Slate and a few worn flints in sand cemented by the oxides 



of iron and manganese. 



m. De la Beche notices (Report, p. 426) the old dunes of consoli- 

 dated sand, between Gwythian and Godrevy Head, which he distin- 

 guished from the underlying raised beach. 



17. Observations of the Fistral Bay Cliffs made here and there 

 proceeding northward. 



a. South end of the Bay (section obscured in places). Coarse brown 

 semi-consolidated sand, with planes resembling bedding and false 

 bedding, containing occasional lines of small angular slate and quartz 

 fragments, 20 feet thick, seems to underlie Head, shown in a reced- 

 ing part of the cliff. At the base of this old blown sand, a trace of 

 blackish coarse consolidated sand binding pebbles of slate and quartz 

 is visible at from 4 to 5 feet above high water. 



b. The basement beds consist of gravel of small quartz pebbles, 

 with fair-sized quartz and slate pebbles, and large subangular slate 

 fragments in blackish sand,. 1 foot to 18 inches thick, with few peb- 

 bles and of a brick-red colour in places ; overlain by fine blackish and 

 reddish brown sand with a few pebbles through it, from 2 to 3 feet 

 in thickness. 



c. The basement beds are represented by two beds of small quartz 

 and slate pebbles and subangular stones, 6 inches and from 6 inches 

 to a foot thick, respectively, separated by 18 inches of coarse blackish 

 sand. 



d. Coarse consolidated sand of slate and quartz and comminuted 

 shells rests on a pebble bed 2 feet thick, and at base 5 feet above 

 high water. The pebbles are of slate, quartz, and occasionally flint ; 

 quartz predominates ; the matrix is coarse grey sand. 



e. Cliff-section toward the north of the Bay — 



Recent blown sand 



Sandy soil with angular fragments of slate 



Buff loam with angular stones and boulders 



Buff sand 



Coarse and fine gravel of quartz, dark grey grit, slate and 



occasionally flint 4ft. Oin. 



/. Near the above old blown sand is shown consisting of brown 

 consolidated sand in laminae about one-eighth of an inch thick, con- 

 taining pebbles for 4 feet upwards from its base, which is about 10 

 feet above high water. 



g. About 100 yards from the above a trace of consolidated sand 

 binds pebbles at about a foot above high water. Old consolidated 

 blown sand is shown in the cliff above ; overlain by Head, capped 

 by recent blown sand. Two whole shells of Patella were found 

 near the base of the old blown sand, which forms a tough, bedded 

 rock, hardening on exposure to the weather. 



h. Dr. Paris (T. R. Gr. S. Corn. vol. i. p. 7) described the old beaches 

 of Fistral Bay and New Quay as a horizontal bed of pebbles, 10 to 



3ft. 



Oin. 



2ft. 



Oin. 



2ft. 



Oin. 



1ft. 



Oin. 



