WALTON COMMON EXPOSING LONDON CLAY ETC. 167 



sand. This peculiarity explains why splendid forest trees, oaks, 

 beeches, &c. flourish on a surface which you can scarcely coax into 

 growing a radish. When once such trees get their roots into the 

 slightly clayey gravel of the plateau they are safe ; meanwhile 

 innumerable firs with their wide-spreading roots are luxuriating in 

 the Top Sand. 



As regards its composition, it is esseiitially a mixed deposit, 

 containing a few split flints, which become more abundant lower 

 down, also numerous large and often rounded quartz grains, the 

 presence of which serves to distinguish it at once from the " soft 

 sand " of the Bagshots. On examining the finer portions under the 

 microscope, it becomes probable that these latter, directly or indirectly, 

 have contributed largely to its formation ; but there is a greater 

 preponderance of quartz together with rather more investment of 

 the individual grain. The " green grains " are very scarce, but 

 there are several granules of iron-oxide, some of which adhere to 

 the magnet. I^Tearer the surface, where a carbonaceous investment 

 discolours the granules, the sand has a blackened appearance, and 

 this is what passes for soil in Oatlands Park. 



By way of comparison with the section through Walton Common, 

 I append a section in the village of Oatlands, close to the 100-feet 

 contour : — 



ft. in. 

 fl. Discoloured sand with root fibres, and occasionally 



j large flints 2 



Top Sand, J 2. Band of flints and flint pebbles in the sand 2 



&c. ' 3. Foxy sands, sharp in the upper part, but rather 



i more earthy towards the base 1 



{4i. Line of flint much bleached : variable in thickness. 2 



3 4 



r Rounded and subangular flint-gravel in deep red sand, 

 Plateau- J in buff-coloured paste, and at bottom in chocolate- 

 gravel. 1 coloured sand : bedding, where discernible, often 



[_ twisted, sometimes nearly vertical 4 2 



Total superficial beds 7 



These rest upon the " soft sands " of the Bagshots of No. 3 type. 

 The well here is 35 feet deep, and probably, like many of the wells 

 hereabouts, does not go completely through No. 3 Bagshots, the 

 water being held up by a pan in the sand, which is much preferred 

 to going down into the " blue stuff." The water of this well is 

 slightly chalybeate, but very good if not allowed to stagnate. It 

 possesses considerable solvent action, I am inclined to think, on 

 iron pipes, and has a very small solid residue on evaporation. Not 

 long ago Mr. Gray, the principal well-sinker, whilst cleaning out 

 one of the wells in the neighbourhood, had the misfortune to break 

 the pan, when he forthwith lost all his water, and had to go many 

 feet deeper before he got it again. 



Kailway-section near names' Bridije. — This is about h mile 

 further down the line than the end of Walton Common, and I went 

 to inspect it on the "27i\\ November, in order to make a rough com- 



