Dr. A. Irving— Sections of Bagshot Beds. 409 
urged ? What were the tracts of sea and land, how deep the water, 
how high the land? What is the explanation of the appearance of 
fluviatile shells among oceanic exuvie ?” The subject as thus 
sketched is, it will be admitted, one of far wider and more general 
interest than such minor questions (which crop up in connexion 
with it) as can be settled by the ordinary rules of stratigraphy. It 
is easy to indulge in premature speculation on the subject ; but 
sound inductive science requires the slow and patient antecedent 
process of accurate observation, and a record and comparison of 
facts. While feeling our way to such ultimate conclusions as may 
be established, not on an aggregation of opinions or ‘ views,’ but as 
rigid inductions from facts, many minor inductions must of course 
be made and criticized, some of which will have to be abandoned in 
the light of fuller knowledge. It is therefore desirable that, when 
exceptional facilities occur (such as were presented to Prof. Prestwich 
some 40 years ago at Goldsworthy), a careful record of the facts 
should be preserved. 
The present paper will be mainly occupied with the detailed 
description of some sections at Finchampstead, Berks, in which the 
whole complexus or group of the Middle Bagshot Beds is exposed. 
One or two of these sections have been referred to on previous 
occasions by myself! and by other writers,? and in one instance a 
sectional drawing has been given.? Convinced, however, that that 
was not exactly in accordance with the facts, the author (Oct. 1886) 
got some rather extensive excavations made in the old clay-pit on 
the north side of Wick Hill near Ninemile Ride, and the section thus 
obtained, when correlated with the open section in the California 
brickyards on the other side of the road, the levels being taken 
from one spot to the other (a distance of 3830 yards), was found to 
furnish the details given in the figured section of this paper (p. 411). 
In these combined sections in the Wick Hill clay-pit, and in the 
California brickyard,‘ the Middle Bagshot beds are seen to attain 
a thickness of about 50 feet as compared with quite 70 feet in the 
well at Wellington College. This diminution is entirely at the 
expense of the green-earth series (Nos. 7 and 8 of the latter section). 
This, as I have shown in recent papers read before the Geological 
Society, is found to be the case generally, the 41 feet of the well- 
section dwindling down to 20 feet in a distance three-quarters of 
a mile to the north, the attenuation of those beds being complete 
before we reach Easthampstead. In this section they may be repre- 
sented by only 16 feet, while the upper clay-bed (9 feet thick at 
Wellington College, and 6 feet thick in the Station cutting) is here 
seen developed to 10 feet, the boundary-line between it and the 
bed next below being drawn where patches of green earthy sand 
first appear. This is not the only case in which this bed is found 
to assume a greater thickness as we approach the London Clay; at 
Q.J.G.S. vol. xli. p. 504. Wick Hill is named on some maps ‘ Upwick’s Hill.’ 
QJ.G.S. vol. xlii. p. 408. 
loc. cit. fig. 2, p. 409. 
Sections P and Q of my last paper (Q.J.G.S. vol. xliv. p. 172). 
em OO WwW = 
