444 



ME. W. H. HUDLESTON ON THE 



The generalized section serves to show how deeply the Bagshots are 

 cut into, there being no less than three places where No. 3 is cut 

 through to the level of the line. The spot where the old section 

 actually terminates is a few yards to the westward of the third gap, 

 where the plateau-gravel is of very great thickness. 



2. Continuation Section (fig. 1). 



It is now proposed to carry the original section 300 yards further to 

 the westward. The east end of the new section (fig. 1) coincides 

 with the boundary between Walton Common and Oatlands Park. 

 For the space of 45 yards or thereabouts the pale buff sands of 

 No. 3 Bagshots may be traced beneath the immense thickness of 

 plateau -gravel. When last seen (about the point indicated by the 

 arrow in fig. 1) this sandy series is strongly current-bedded, with a 

 false dip of 7° towards the west. Then occurs a kind of hiatus 

 where nothing is seen but portions of plateau-gravel. Yet a little 

 further on and the clays of No. 4 are well seen on the bank-side, 

 and very soon at least 12 ft. of these beds can be measured on the 

 slope. The actual junction with the presumably underlying No. 3 

 series is nowhere visible by reason of the extensive denudation 

 which the clay series has undergone towards its outcrop. But 

 evidence of the former extension of the clay series in this direction 

 may be seen in the clayey nature of portions of the material com- 

 posing the so-called plateau-gravel at this point (n in fig. 1). 

 Altogether the evidence is very much in favour of the clay series 

 resting upon the sandy series, and not passing into it by a process of 

 lateral change, as is stated to be sometimes the case. And there is 

 an additional proof of the truth of this view, that for some distance 

 beyond gap No. 4 the line remains quite dry, as though the 

 argillaceous series, so visible on the slope, did not extend quite 

 down to the level of the permanent way. Presently the effects of 

 the clay begin to be felt upon the line, and throughout the remainder 

 of the section the unballasted portion is a perfect quagmire. The 

 influence of this clay is felt upon the line considerably further than 

 the section extends, owing to the impermeable surface throwing out 

 all the water which percolates the overlying loose sandy series 

 (No. 5). There is an appearance in the upper part of the clay 

 which seems to indicate erosion previous to the deposition of the 

 overlying sandy series (No. 5) ; but this is doubtful, and in the 

 present state of the section it is impossible to clear up that doubt. 



3. Composition oe No. 4 Bagshots. 



Towards the east end thin seams of a pale-coloured loam, resembling 

 the so-called pipe-clay, form the upper part of the series, alternating 

 with brownish sands, which are rather coarser in the grain than 

 those of No. 3. Lower down these seams are observed to be thicker 

 and the clays less bleached. As we proceed westwards the blue 

 beds (4 1 ) occupy the slope, and the greater part may be described as a 



