OjS: the BAGSHOT beds of the LONDON' BASIN. 405 



The Nokth-west of Bagshot HE.vTn. 



Still further westwards we come to an outlier of the Bagshot 

 Beds at Wick Hill, near Bracknell, mapped as Lower Bagshot on 

 the Geological map, but according to Mr. Irving consisting of Upper 

 nnd Middle Bagshot (Quart. Journ. Geol. Soc. vol. xli. p. 505 ; Proc. 

 Geol. Assoc, vol. ix. p. 223). This outlier is thus described in the 

 Survey Memoir (vol. iv. p. 316) : — " At Wick Hill, north of 

 Bracknell, the 2)assage-hed (of the Lower Bagshot Sand) may be seen 

 resting on chocolate-coloured London Clay in a brickyard. Here 

 .there may be seen several layers of flint pebbles, six inches or so 

 thick, separated by layers of sand and pipe-clay." Other observers 

 (e. g. Professor E-upert Jones, in the discussion on Mr. Irving's paper, 

 Quart. Journ. Geol. Soc. vol. xli. p. 509) have stated that there is 

 an apparent unconformity between the Bagshot Beds and the London 

 Clay at this place. 



As therefore this outlier has been the subject of such divergence 

 of opinion, we will record the result of our observations at some 

 length. At the top of Wick Hill, just below the last letter in that 

 name on the new one-inch map, there is a pit in yellowish, rather 

 coarse sand, in and upon which is a considerable mass of pebbles. 

 The surface has been rearranged, as is shown by the presence of 

 angular flints, but some five or six feet down the pebbles appear to 

 be in situ in the sand. Further north are two brickfields near the 

 edge of the outlier. That to the east shows about eight feet of ' 

 numerous contorted layers of yellow sand and pipe-clay, with nume- 

 rous irony concretions, and a small pebble-bed near the base, resting 

 on dark- coloured London Clay. 



That to the west shows fine yellow sands, false-bedded, without 

 pipe-clay, resting on the London Clay ; and in the lane close by, at 

 a rather higher level, a pebble-bed occurs in the sands, but this 

 contains some angular flints, and has the appearance of having 

 been re-arranged. 



When one of the authors visited these brickfields some years ago, 

 he thought he saw what looked like an unconformity between the 

 London Clay and the Bagshot Beds ; but this appearance is not now 

 to be observed, and was probably due to false-bedding. We are, 

 however, unable to agree with the Survey that there is here a 

 passage-bed between the two formations. Nor can we agree with 

 Mr. Irving that this outlier consists of Upper or Middle Bagshot 

 beds. The light and dark yellow sands, bands of pipe-clay, and 

 pebble-beds agree so well with the proved Lower Bagshot beds, 

 already or hereafter to be described, that we have no hesitation in 

 calling them Lower Bagshot, in the absence of any evidence to the 

 contrary ; but if there could be any doubt, the entire absence of the 

 green-sand bed which crops out at Caesar's Camp, Easthampstead, and 

 is no more seen north of that point, is to our minds quite conclusive. 



We visited the railway-cutting at Bracknell, described by 

 Mr. Irving (Q. J. G. S. vol. xli. p. 505 ; Proc. Geol. Assoc, vol. ix. 

 p. 223), but found it much overgrown. The small section exposed 



