Note on the Walton Common Section. 221 



shots. The Ash-station well shows the basement-beds of the Lower 

 Bagshots, of a character very similar to those in the Brookwood and 

 South-Camp deep boring. The position of the outcrop of the London 

 Clay also is in favour of a regular and persistent northerly dip, 

 corresponding in degree with that given at East Wyke farm by 

 Messrs. Monckton and Herries. The thickness of the London Clay 

 was calculated at 330 feet, which is about the same as at South Camp, 

 leaving no margin for its erosion before the deposition of the Bag- 

 shots. 



The third section was drawn, also on the same scale, through Alder- 

 shot town, showing the beds from the Woolwich and Reading series 

 to the Middle Bagshots inclusive. The dip is 2|° to the N., and 

 regular, as in the other two cases. The following thicknesses are 

 given : — ft. 



Middle Bagshots about 55 



Lower Bagshots „ 115 



London Clay „ 335 



It was inferred from various calculations, as also from direct obser- 

 vation, that the thickness of the London Clay shows no diminution 

 throughout the section, being nearly the same also at Ash and at 

 Aldershot Place. 



In " Caesar's Camp " the Pebble-bed occurs at altitudes ranging 

 from 500 to 550 feet. 



The Author concluded that wherever we can fix the top or base 

 of the London Clay we get a northerly dip of 2|° to 3°, showing a 

 fairly constant thickness of from 330 to 340 feet. The same thing 

 occurs from Odiham on the west to Ash on the east, whilst at 

 Brookwood the London Clay is thicker. He also assumed the exist- 

 ence of a passage from the London Clay up into the Bagshot beds in 

 the deep wells or borings at Wellington College, at Brookwood, and 

 at South Camp. Hence at these points there can have been no 

 great erosion or unconformity. The overlying Bagshots lie conform- 

 ably on the London Clay and on each other. 



2. " Supplementary Note on the Walton Common Section." By 

 W. H. Hudleston, Esq., M.A., F.R.S., Sec.G.S. 



The principal object of this paper was to point out the occurrence 

 of certain beds of clay or loam in what are usually known as the 

 " Lower Bagshot Sands " of West Surrey. It was shown that the 

 sandy series, no. 3, of the previous paper is overlain by a second 

 clay series, no. 4, whose mode of occurrence and lithology were de- 

 scribed. This is again succeeded by a third sandy series, no. 5, 

 which, it is believed, is maintained throughout the remainder of the 

 cutting as far as the River Wey, with occasional clay patches de- 

 posited in small basin-shaped hollows of the sand. 



The nature and geological position of the brick-earth of Hatch 

 on Woburn Hill was next described. This forms a portion of the 

 " clays most extensively developed between Addlestone and Chert- 

 sey," referred by Prof. Prestwich to his Middle Bagshots, and 

 mapped as such by the Geological Survey. The clay is seen to 



