378 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 20, 



2. On the main points of Structure and the probable Age of the 

 Bagshot Sands, and on their presumed equivalents in Hamp- 

 shire and France. By Joseph Prestwich, Jun., Esq., F.G.S. 



In continuation of the paper I had the honour of reading before the 

 Society on the 3rd of February last, I purpose now to examine an- 

 other division of the Eocene series, frequently incumbent upon the 

 London clay in the neighbourhood of London, and commonly termed 

 the ^^ Bagshot Sands." 



Forming usually barren sandy districts, and rising, over great part 

 of their area, into ranges of heath-covered hills, the Bagshot sands 

 have attracted but little attention, having, although so near London, 

 remained comparatively unexplored since Mr. Warburton described 

 them in 1821*. 



Without any permanent natural sections, and with few artificial ones 

 beyond an occasional sand or clay-pit, and the curious grave-shaped 

 excavations often scattered over the surface of the gravelly heaths on 

 some of the hills, where they are formed in the process of digging out 

 of the sands the occasional masses of concretionary sandstone, the 

 almost only opportunities for studying the structure of the Bagshot 

 sands are aiforded by fresh roadside sections and railway cuttings. 



The fossils are as rare as the sections. The three generaf (for the 

 species were not distinguishable) of testacea found by Mr. Warburton 

 at Chobham, and the subsequent notice by Dr. Buckland in 1838 of 

 the remains of fishes (including the determination of three new genera) 

 at Goldsworthy, near Woking, comprise I believe all J at present 

 known of the palaeontology of the Bagshot sands §. 



Notwithstanding however the scantiness of their recent flora and 

 the poverty of their ancient fauna, the Bagshot sands present many 

 features of much interest. Superimposed on the more fertile London 

 clay, from whose rich and well-wooded valleys they frequently rise in 

 abrupt hills and steep slopes, they often command views of much 

 beauty and considerable extent, and in striking contrast with their 

 own uncultivated and open but fresh and healthful tracts. Of this 

 the rich and varied prospects from St. George's Hill near Weybridge, 

 St. Anne's Hill and White Hill near Chertsey, Cooper's Hill near 

 Egham, Hungary Hill near Farnham, and Farley Hill near Swallow- 

 field, are well-knovm examples |1 . Nor are the Bagshot sands them- 



* Trans. Geol. Soc. 2nd Series, vol. i. 



t Casts of Crassatella, a Pecten, and what appears to have been a Trochus 

 (Trans. Geol. Soc. 2nd Series, vol. i. p. 51). 



X Indistinct traces of vegetable remains have also been noticed in some of the 

 blocks of concretionary sandstones. 



§ With the exception of a few occasional specimens, rarely collected, I am not 

 aware of the existence of any regular collection of the " Bagshot-sand'^ fossils, even 

 of a local nature. I shall be glad to be informed of any. 



II The general average height above the level of the sea of the " massif" of the 

 Bagshot sands varies from 100 to 200 feet. From above this general level the 

 ranges of hills which constitute so large a portion of the area of these sands, rise 

 from 150 to 200 feet. St. Anne's Hill is 240 feet high, Goldsworthy Hill 185 feet ; 

 Farnborough station 200, Winchfield station 250, and Bagshot Heath 463. In the 

 section No. 2 the heights are taken from the railway levels. For the heights of 

 many places in this and the adjacent districts see Dr. Fitton's useful list (Geol. 

 Trans. 2nd Series, vol. iv. p. 369). 



