﻿20 MR. W. HILL ON A DEEP [Feb. I908, 



immediately sourh-west of the Union Workhouse, about 25 feet of 

 Drift is exposed. This pit is in a mass of Drift banked against the 

 western Chalk-knoll ; it forms a ridge extending for some little 

 distance towards the north, which gradually descends to the Lower- 

 Chalk plain. The material seen here consists chiefly of subangular 

 and rounded flints with a large proportion of chalk-pebbles, together 

 with Jurassic and Carboniferous limestones, ironstone, pebbles of 

 quartz and quartzite, and red chalk. In some parts the stratifi- 

 cation is even and regular, in others the bedding is contorted, and 

 the strata dip at a high angle in more than one direction. From a 

 thin bed of blue clay I picked out a chalk-pebble showing striations 

 which were obvioasly due to ice-action. 



Near the Vicarage (235 feet O.D.) a recently-opened pit yields 

 the following section : — 



Thickness in feet. 



Gravelly soil 3 



Chalky Bouider-Clay 4 



Pale-grey clay 2^ 



Pale-brown sandy silt, with discontinuous layers 



of fine chalky gravel 3J 



Sandy gravel seen for about P2 



The clay which follows the Boulder-Clay is quite free from stones 

 and is much like Gault ; moreover, it contains many whitish concre- 

 tions similar to those in the upper part of the Gault at Arlesey. The 

 gravel, as usual, consists of rolled and subangular flints and chalk, 

 with a varied assemblage of other rocks, many gryphaeas, belemnites, 

 etc. This section is quite close to the platform of Chalk mentioned 

 on p. 15, and the beds dip at a high angle towards it, to the west. 

 Bare Chalk occurs 100 yards to the north, and about 250 yards to 

 the south-west. There are many gravel-pits on the high ground to 

 the south and east of the town, all of which are in the Drift banked 

 against the eastern knoll. At Highbury (300 feet O.D.) is a shallow 

 pit from which a clayey gravel has been dug. This gravel contains 

 big blocks of limestone and sandstone, large and small chalk-flints 

 and chalk-pebbles. The depth to which the gravel is dug is governed 

 by what appears to be Boulder-Clay. 



Cleaner gravel is to be seen in a pit belonging to Mr. Theodore 

 Ransom, about 300 yards south of the last. [This also was shallow, 

 but a thickness of 25 feet of gravel was exposed here in January 

 1908.] 



A few hundred yards still farther south, Messrs. Logsdon & 

 Jackson work another pit. This shows a face of nearly 30 feet, and 

 the section of the northern part of it seen in June 1907 was as 

 follows :— 



Thickness in feet. 



Gravelly soil 2>\ 



Sharp sandy gravel, chiefly small flints and chalk-stones... 4^ 



Sandy loam, with seams of chalky gravel 3 



Quartz-sand with much fine chalk, small flints, and chalk- 

 pebbles 2^ 



Coarse gravel, in well-marked layers divided by seams of 

 loam or sharp sand, seen for about 15 



