448 EOCENE. 



Upper Bagshot Beds. 



This division consists of white and pale-yellow, and sometimes 

 mottled sands, showing no distinct lines of bedding, and rarely any 

 false-bedding. 



In the Isle of Wight the beds are exposed at Alum and Whiteclifif 

 Bays, having a thickness of from 140 to 200 feet.' Casts of bivalves, 

 Tellina, etc., are occasionally found in ironstone, but on the whole 

 organic remains are rare. Being developed at Headon Hill, the 

 term Headon Hill Sands has been used, but the name is inconvenient 

 on account of the Headon Beds which occur above ; the name 

 Barton Sands has been suggested by Mr. H. Keeping, because the 

 fossils connect the beds with the Barton Clay below, and indeed 

 the term Bartonian has been used to include both Barton Clay and 

 Upper Bagshot Beds. Between Long Mead End and Paddy's 

 Gap Ravine, near Milford, on the Hampshire coast, a bed was 

 discovered by Mr. S. V, Wood, which yields Neriiina co7icava, 

 Cerithiu?n concavum, C. pleurotomoides, Cyrena cycladi/orviis, etc. 

 This occurs above the Barton Clay, and furnishes evidence of an 

 estuarine transition into the Lower Headon Beds.- 



The age of the so-called Upper Bagshot Beds in the London 

 Basin has been questioned ; Mr. J. S. Gardner indeed doubts 

 whether Upper Bagshot Beds are represented in this area, owing 

 to the absence of the Barton Clay and the similarity between the 

 sands in Surrey, etc., and those of Highcliff, Hengistbury, and 

 Boscombe in Hampshire, which are grouped with the Bracklesham 

 Beds.^ (See p. 447.) These Upper Bagshot Beds are developed 

 on Frimley and Chobham Ridges, and in the heaths of Bagshot, 

 Hartford and Sandhurst, where their thickness varies from 120 to 

 300 feet. They contain few pebbles, and few, if any, clay bands, 

 but they have an abundance of ferruginous concretions, which some- 

 times contain casts of marine shells. The fossils collected by Mr. 

 H. W. Monckton and others, from Frimley and Pirbright, show 

 that the beds, like the Headon Hill Sands, are intimately connected 

 with the Barton Beds. Among the species are Lucrna mitis, Peden 

 reconditus, Cardita sulcata, Tellina scalaroides, Oslrca flabelhda, Natica 

 ambulacrum, Tiirritella imbricalaria, etc.* 



In the Isle of Wight the Headon Hill Sands have been ex- 

 tensively worked for making glass. 



Greywethers. — Scattered here and there over the southern and 

 south-eastern parts of England, we find large blocks of hard 



1 Bristow, Geol. I. of Wight, p. 51. 



2 London Geol. Journal, No. i, 1846, p. I ; S. V. Wood, jun. G. Mag. 1883, 

 p. 493, 1884, p. 65 ; H. Keeping, Ibid. p. 95 ; H. W. Monckton, Q.J. xxxix. 353. 



3 G. Mag. 1879, p. 151 ; Q. J. xxxv. 210. 



* See Piestwich, Q.J. iii. 393 ; Whitaker, Mem. Geol. Surv. iv. 333 ; W. H. 

 Heiries, G. Mag. 1881, p. 172; H. \V. Monckton, Q.J. xxxix. 352; H. W. 

 Monckton and R. S. Henies, Q. J. xlii. 415 ; T, R. Jones, P. Geol. Assoc, vi. 433. 



