ON THE WALT0N-C0:\OI0N SECTION. 



443 



32. Supplementary Note on the Walton-Coioion Section - . By W. 

 H. Httdleston, Esq., M.A., F.R.S., Sec. G.S. (Bead April 27, 

 1887.) 



1. Recapitulation of some points in the previous paper. 



2. Continuation section. 



3. Composition of No. 4 Bagshots. 



4. Remainder of the cutting. 



5. The Brick-earth of Hatch. 



6. Its probable Geological Position. 



7. • Conclusion. 



Theee seems to be so much uncertainty as to the character of the 

 basal beds of the Lower Bagshots in the London Basin that anv 

 opportunity which affords us unmistakable evidence of their real 

 nature should be seized without delay. We have had so much 

 theorizing, based upon the evidence of well-sections and of limited 

 exposures, that we turn with pleasure to a good continuous section 

 like the one which has lately been disclosed between Walton and 

 Weybridge on the London and South-Western Bailway. The main 

 features of the Lower Bagshot series in this section, at its actual 

 junction with the London Clay, were very fully described by me in 

 a communication made to the Society last year. Whether we 

 regard the junction there shown as evidence of an unconformity or 

 otherwise, the fact of a complete lithological change is patent to all. 



1. Recapitulation oe some Points in the peeviotjs Papee. 



Hesting immediately upon the grey- coloured and sticky London 

 Clay, distinguished by its fine and perfectly regular bedding, is a 

 sharp yellow sand full of current-bedding. This yellow sand I 

 dubbed " No. 1 Bagshots." Then follows the first clay series, 

 which I called No. 2, or the " Blue Bagshots." It is surmounted 

 by a second sandy series, referred to in my previous paper as " No. 3 

 Bagshots." As far as the new cutting for the widening of the line 

 had then progressed, there was no reason to suppose that No. 3 was 

 succeeded by a second clay series, beyond the fact that the line is 

 rather wet thereabouts. For some reason the contracter left this 

 piece un excavated, and even now (end of March 1887) this portion 

 has not been fully excavated, so that there are one or two points 

 which cannot be ascertained by actual observation. 



The previous sections (Q,. J. Gr. S. May 1886, pp. 148, 157) refer 

 entirely to Walton Common. The one on p. 148 is merely a gene- 

 rnlized section of the portion of the cutting then under description, 

 whilst the details of the Lower Bagshot beds given on p. 157 are not 

 continued to the end. Hence the section now offered (fig. 1, p. 445) 

 must be fitted on to the west end of the generalized section, which 

 gives no details of the Lower Bagshot Beds, but merely represents 

 their position with reference to the London Clay and Plateau-graveL 



