264 A. J. JUKES- BROWNE (EST THE RELATIONS OF 



cated it in his rough copy when mapping part of the Bedfordshire 

 sheet. In this respect, therefore, I am in entire agreement with 

 my colleagues of the Geological Survey and their published maps. 



At Eaton Bray, on the borders of Buckinghamshire, occurs the 

 first trace of any thing like the true Upper Greensand ; this is 

 marked as an inlier on the Survey Map. The following beds are 

 seen in the brick-yard : — 



3. Pale grey marl 6 feet. 



2. Greenish sandy clay 6 „ 



1. Blue sandy clay (said to be below) — 



These beds are certainly something like the top part of the Upper 

 Greensand further west. 



§ 3. Gault and Upper Greensand of Buckinghamshire. — Still follow- 

 ing the same horizon, further evidences of true Upper Greensand are 

 shortly met with — sooner, indeed, than would appear from the Survey 

 Map ; for though along the gentle slope of the hills between Eaton 

 Bray and Buckland the junction is nowhere to be seen, yet at the 

 outlier of West End a few feet of clayey greensand and sandy marl 

 overlie the Gault, and clearly represent the Upper Greensand ; this, 

 therefore, would probably be discovered on the opposite escarpment if 

 there were any cuttings, ponds, or pits to expose it. 



At Buckland, near Tring (see Map, p. 259), the Upper Greensand 

 has thoroughly set in ; and nearly opposite the church is a small 

 pond where the following beds are shown in the bank : — 



ft. in. 



3. Pale green sandy marl 2 



2. Yellowish green marly sandstone 1 



1. Green sandy clay 1 6 



In the stream more than half a mile S.E. of Aston-Clinton church 

 Mr. Whitaker in 1864 saw a fresh-cut section, which appeared as 

 follows : — 



3. Greensand, partly of a deep rich colour. 



2. Flaggy calcareous sandstone, with occasional marly beds. 



1. Greenish sandy clay (top of Gault). 



From this point the Greensand gradually increases in thickness, 

 and passes into the form under which it is well known in Oxford- 

 shire and Berkshire, where it always consists of two members — an 

 upper division of soft green sands and a lower stratum of hard 

 calcareous firestone. 



Mr. E. C. Davey, of Wantage, has kindly given me some par- 

 ticulars of the beds near that town. The soft sands are there about 

 30 feet thick, are fossiliferous at the top, and are immediately suc- 

 ceeded by Chalk- marl. The firestone contains sponges and Echino- 

 derms ; but the bed is only 6 feet thick. 



The thickness of the whole formation, indeed, seems to be very 

 variable, as the following figures will show — Eisborough 60?, 

 Cuxham 70, Didcott 120, Wantage 36, Woolstone 60, Devizes 138. 



It is everywhere succeeded by the basement beds of the Chalk- 

 marl, the Chloritic Marl being apparently absent, unless represented 

 by the uppermost soft green sands. 



