170 



ME. W. H. HXJDLESTON ON A SECTlOi!^^ TKKOUGH 



Hence this deposit can only be called a "gravel" by courtesy. 

 Specimens of the hardened beds of the Lower Greensand are of 

 occasional occurrence. 



Altogether this is an eminently local deposit, and seems to have 

 been derived largely from the green sands and loams of the upper 

 division of the Middle Bagshots, which ought to form the last 50 

 feet of St. George's Hill. It is not difficult to imagine that, when 

 the climate was colder, the steep northern slope of St. George's Hill 

 was occupied by a kind of neve, or a sliding mass of indurated 

 snow. This, adhering to the green-sand beds, caused large masses of 

 them to slide downwards, iiwolving also a portion of the original 

 plateau ; hence the occasional jambs of flint-gravel. That this was 



Pig. 



8. — Contorted Series overlying Middle Bagshots^ St. George's 



mi 



pusned over the clay beds of the Middle Bagshots is perfectly clear 

 from the way in which these latter are squeezed up and involved in 

 the superficial mass. At the same time we may admit that the 

 contours are not quite the same now as when this deposit was 

 formed, and that the deposit itself is merely a remnant of a much 

 larger spread which may have occurred about this level. 



Summary. — The section on the London and South- Western 

 E,ailway above described shows : — 



(1) That the " Top Sand" of Oatlands Park, in a modified form, 

 extends at least as far as Walton Station, and covers the entire 

 surface, though thicker over the Bagshot-Sand area than over the 

 Loudon-Clay area. 



(2) That the valley-slope, west of Walton Station, consists of a 

 curious mixture of gravel and clay, and that this " Mixed Series " 



