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



f. Near the centre of Perleze Bay a few quartz and slate pebbles 

 are present, under blown sand, at about five feet above high water. 



g. The cliffs of the cove north of Trevone (2 miles west of Pad- 

 stow) are from 5 to 15 feet high, and occasionally capped by coarse 

 brownish sand, giving place to dark brown clay with angular slate 

 fragments, and an occasional quartz pebble. The ground slopes 

 upward for a quarter of a mile very gradually. 



20. Between Padstow and Tintagel. 



a. On the cliffs of Bray Hill, near St. Enodock, yellowish and 

 grey, thin bedded, consolidated sand of comminuted shells, con- 

 taining shells of Helices, is visible, at base 5 feet above high water. 



b. In one place the following section occurs under 2 feet of 

 recent blown sand : 



Consolidated sand 6in. 



Dark brown loam, containing angular fragments of quartz, 



slate and grit 2ft. to 3ft. 



Upon greenish grey slates with quartz veins. 



c. Near the mouth of the St. Enodock Valley, a bed of consolidated 

 sand, one foot thick, containing land shells and angular fragments 

 of slate, is capped by recent blown sand, and rests on red and green 

 banded slates at 8 feet above the present beach. 



d. At the stream mouth between Porteath and Trefan Head. 

 Head, of angular stones in brown and yellowish loam, has a stratified 

 appearance in the distance, owing to the sizes and dispersion of the 

 fragments and their partial absence in places. The stream has cut 

 a steep bank at the mouth of its gorge, which exposes 20 feet of 

 Head — brown loam with angular slate and quartz stones, roughly 

 horizontal in arrangement. 



e. By the mouth of the stream west of Port Isaac, between 

 Eoscarrock and Lobber Rock, 20 feet of Head is shown, consisting 

 of angular fragments of slate and quartz in brown loam. 



/. Near Chapel Bock the slates have been cut into reef platforms 

 or shelves, in places, at about high- water level. 



g. At the mouth of the stream gorge west of Dannon Chapel, 10 

 feet of Head is shown, consisting of brown loam with angular slate 

 and quartz stones. 



21. The Scilly Isles. 



Mr. Carne (Trans. R. G. S. Corn. vol. vii. p. 140) mentions the 

 occurrence of redistributed granitic matter, called " secondary 

 granite," on Rat Island, at Piper's Hole in Tresco, and Piper's 

 Hole in St. Mary ; in both the latter caverns it forms the principal 

 part of the roof, and contains boulders or rounded masses of 

 perfect granite, some rather large. 



General Conclusions. 

 Head. — The position of the stony loam or Head in sites where no 

 modern talus could rest ; the denudation it has undergone, and its 

 frequent presence on the cliffs ; prove its accumulation to have 

 taken place subsequent to the formation of the raised beaches, yet 

 considerably anterior to the prevalence of the present climatal con- 

 ditions. It marks, as Mr. Godwin-Austen (Q.J.G.S. vol. vii. p. 122) 



