Dr, A. Irving—Sections of Bagshot Beds. 413 
260), the upper clay, the green earths (at Hast Court) and the lower 
clays and sands of the Middle Bagshot basement-bed, which is seen 
in small road-sections cropping out below the green earths (the 
junction being exposed in section continuously for about 20 yards), 
till we come to about 210 (0.p.) at the village school. Here the 
well just mentioned gives the following sections : 
a. Yellow stiff ferruginous clayey (laminated) sand ........eeeeee 10 feet 
b. Greenish-black sand with pyritous nodules .......0...seeee cece OMe 
c. Running bluish quartz sand with lumps of stiff black clay ........ Sires 
20 feet 
The succession of the whole Middle Bagshot series immediately 
above leaves no room for doubt as to the horizon here. At Long- 
moor (the particulars of this well were given me by the man who 
dug it) the section is as follows :— 
Cem EAVe iypOTIG srs taccasvedetncsesencaccar as: «<i «sjesowscaashuside seatonsnenoes 1 foot 
b. Soft loamy yellowish clay, ‘‘ like that now dug in the California pits, 
DUtp On GUILE|SONSHLON Ge cberescncasicccnstnscce-ceseseccnedeeeeemtedons 3 feet 
CHMS OLGPLOGSEYSAT CWS ks eee Pir e OA e U  ol  2e sal aoeememeasiae 1D). 
16 feet 
This is near the outcrop of the London Clay. 
In my last paper (Q. J. G. S. May, 1888) particulars are given of 
the structure of the Church Hill which forms the westernmost spur 
of Finchampstead Ridges, and of the stratigraphical relation of the 
beds in the Bearwood Hills to those in that hill, from which | still 
maintain that the recognition of the pebble-bed horizon in the 
Barkham pit, and in Coombe Wood, as marking the base of the 
Upper Bagshot, fits in well with the structure of the adjoining 
country. This could easily be shown in a section drawn about north- 
west from Wellington College, so as to include the well-section 
there, the section at the station, and that of a well dug lately (1886) 
behind the Wellington Hotel, the section in the pinewoods near 
Heath Pool,! and the Wick-Hill-California section. 
The facts described in this paper, and in those which have recently 
appeared in the Geol. Society’s Journal, admit of one simple explana- 
tion, and that is a gradual (though not uniform) attenuation of the 
Lower Group of quartz sands (ninety-five feet thick at Wellington 
College) and of the green-earth beds of the Middle Group. In con- 
sequence of this, the gradients of the basement clayey beds of the 
Middle Group, the base of the Upper Group, and the surface of the 
London Clay, form a triad of horizons which approximate nearer 
and nearer to one another as we trace them to the north; and, as 
a further consequence of this, beds of higher horizons overlap in 
places those of lower, and rest upon an eroded surface of the London 
Clay along the line of country by Bearwood, Wokingham, Buckhurst 
and Bracknell, so that we have pretty clear indications of the 
northern shore-limit of the ancient Eocene estuary, traces of its 
affluents being recognized at Ascot and Wokingham. 
Supplementary Note-——In a former paper (Grou. Mac. Dee. III. 
1 Section O (Q.J.G.S. vol. xliy. p. 171). 
