W. A. E. Ussher — Post-Tertiary Geology of Cornwall. 167 



of the raised beach in Gerran's Bay by oxide of iron. Near Pen- 

 dowa the beach is absent, and the Head rests directly on the slates. 



b. Mr. Trist (T. E. G. S. Corn. vol. i. p. Ill) described the raised 

 beach as a flat stratum of sand and pebbles, sometimes occurring as 

 a black sandstone 2 feet in thickness, sometimes as a conglomerate 

 of sand and pebbles 10 feet thick, resting on limestones and argil- 

 laceous schists abounding in manganese, and capped by an argilla- 

 ceous friable earth. 



c. Near Pendover (? Pendowa) beach, Mr. Trist noticed quartz 

 boulders at the Carnes, wholly insulated, and of a different nature 

 from the substratum (vide T. E. G. S. Corn. vol. vi. p. 91. Budge.) 



d. Dr. Boase (T. E. G. S. Corn. vol. iv. pp. 270, 273) mentions the 

 occurrence of " layers of different substances " in the cliffs to the 

 east of Porthscatho and in Gerran's Bay, the inferior 10 feet being 

 much consolidated. One ferruginous layer resembled pudding-stone. 

 The pebbles diminish upwards into pure sand, reddish brown and 

 friable, in layers 8 or 9 inches thick. 



e. (op. cit. p. 275.) At Porth, one mile east of St. Anthony, Dr. 

 Boase noticed beds of sand and gravel ; Porth farmhouses being built 

 on diluvium of regular beds of sand and pebbles, the latter below ; 

 shells, chiefly marine univalves, were found in parallel layers in the 

 sand. The height above high water is not given. 



5. Falmouth. 



a. Coast-section on the N.E. of Pendennis Castle. Head of angular 

 fragments of slate and quartz with a tolerably regular horizontal lie, 

 40 to 50 feet in thickness, contains here and there a few pebbles at 

 its base, which is from 5 to 10 feet above high water. Mr. Godwin- 

 Austen mentioned (Q. J. G. S. vol. vii. p. 121) the occurrence of 30 

 feet of Head on the west of Pendennis Point. 



b. Near Cove Battery the Head is of a greyish colour in the upper 

 part, brownish below ; a line of larger fragments and a band of loam 

 without stones occur in it. 



c. Mr. E. W. Fox (Phil. Mag. and Journ. Science, ser. 3, vol. i. for 

 1832, p. 471) describes the Falmouth raised beach as a horizontal 

 bed of rolled quartz pebbles, gravel and sand (like the present 

 beach), from 1 to 3 feet in thickness, and generally from 9 to 12 feet 

 above the highest spring tides. The Head upon the old beach is 

 described as earth, stones, and detached pieces of rock. The cliffs 

 are from 30 to 60 feet in height. The old beach does not extend far 

 from the cliff face, it was observed in one place at 8, in another at 

 20 feet, within it. Between the parishes of Budock and Mawnan 

 the pebbles appeared to be cemented into a conglomerate, in places, 

 by the oxides of iron and manganese. 



d. Mr. Godwin-Austen (T. G. S. ser. 2, vol. vi.) describes the old 

 beach and overlying Head at Swanpool as purely marine beds pass- 

 ing up into fluvio-marine and fluviatile accumulations. 



e. Between Pennance Point and Maen Porth (Fig. 1), a bed of 

 pebbles, chiefly quartz, with slate boulders, is visible, under Head of 

 angular fragments in loam, at intervals. In one place the beach 

 consists of quartz pebbles in grey and reddish brown sand, with 



