234 Proceedings of Philosophical Societies. [Sept. 



A paper, on the Bagshot Sand, by Henry Warburton, Esq. 

 VPGS. was read. 



The sand of Bagshot Heath occupies a district of about 25 

 miles in length, extending from east to west along the axis of 

 the chalk of the London basin ; commencing at Esher, in the 

 county of Surrey, and terminating at Bromshill Common, on the 

 confines of Berkshire and Hampshire ; its greatest breadth in a 

 line drawn from Hungry Hill, near Farnham, to Oakingham is 

 about 12 miles. The course of its southern boundary is marked 

 by those sandy elevations, which, beginning at Esher, extend to 

 Painshill, Breach Hill, and Ockham Hill, near Ripley. At 

 Tukebury Hill, and Beacon Hill Camp, immediately south of 

 Farnham, it attains its greatest elevation ; and approaches 

 within less than a mile of the ridge of chalk which forms the 

 southern limit of the London basin. From Beacon Hill Camp, 

 its western boundary may be traced over a low moorish country 

 to Hertford Bridge, where it again acquires considerable thick- 

 ness, forming a regular escarpment to Broomshill Common. 

 There its northern boundary commences, passing to the hill 

 above Egham, and forming a line of sandy hillocks, parallel to 

 the valley of the Thames, and at no great distance from the 

 river, by St. Ann's Hill and Oatlands, to the eastern extremity 

 at Esher. 



At Egham Hill, the sand is observed resting immediately on 

 the London clay, and there is every reason to believe that it 

 retains the same position throughout the district which it occu- 

 pies. Those parts which are nearest to the surface are generally 

 more or less mixed with angular chalk flints, and other diluvian 

 debris ; such as are found upon almost every part of the London 

 basin. The highest of the undisturbed beds consist of a meagre 

 and somewhat ochreous sand, without any angular masses of 

 flint; and, at a lower level, beds of foliated green clay, alternat- 

 ing with beds of green sand, occur, as may be observed to the 

 north of Chobham Park, on the road from Chertsey to Bagshot. 

 Below these beds are found alternating strata of white, sulphur 

 yellow, and pinkish foliated marls, containing abundant grains 

 of green sand regularly stratified, and inclosing fossil shell, 

 which have not hitherto been found in England in any other bed 

 above the chalk. These lowest beds, which may be seen in 

 descending the acclivity to the south of Chobham Park, appear 

 to be about 40 feet thick. Of the shells found in them, the most 

 abundant is the cast of a crassatella, agreeing with one found in 

 the Paris basin at Meudon in the calcaire grossitre a matiere 

 verte. 



At St. Ann's Hill, the beds which lie nearest to the London 

 clay consist of masses of rolled chalk flints resembling those of 

 the pebble bed in the plastic clay, intermixed with green sand, 

 green foliated marl, and stony concretions of the sandstone, 

 which are so generally disposed in masses over the surface of 



