124 PKOF. J. PEESTWICH ON THE RELATION OF THE 



P.G.S. *, a notice of many of the hill-gravels of the London district, 

 including the outliers on Shooter's Hill, Warley, Epping, Langdon 

 Hill, and others, which he refers, with Mr. S. Wood, to the wreck of 

 local Bagshot Beds. 



The admirable " Drift Edition " maps of the Geological Survey, 

 show the intricate ramifications of the Glacial and Post-Glacial 

 Drifts in Sujffolk, North Essex, and part of Herts (Maps 48, 47 t, 

 and part of No. 7) ; but the Pebbly Gravel (Westleton) in Essex J, 

 owing, I presume, to its being almost invariably hidden under 

 Glacial beds, is not represented. Although, however, in that county 

 the Westleton Beds are generally covered by Boulder-clay, the 

 cuttings on the Great Eastern Eailway which I had the oppor- 

 tunity of seeing showed that throughout that district they pass 

 under the Glacial Series, and so help to connect the Hertfordshire, 

 Buckinghamshire, and other outliers with the Westleton Shingle 

 of Suffolk. These sections I will now proceed to describe. 



2. Range inland of the Westleton Beds. 



Suffolh. — In the westward range of the Westleton Beds, sands 

 predominate in some j)laces, shingle in others — often finely stratified 

 and false-bedded. Besides their distinctive composition, they may 

 generally be distinguished at sight by their pure white or ochreous 

 colour, in contrast with the red of the Crag or the light drabs of 

 the Glacial gravels. They pass, south of Westleton, from off the 

 Chillesford Clay on to the unproductive sands of the Crag, as shown 

 in the following section (fig. 1) : — 



Eig. 1. — Pit on RundelVs Farm, Leiston Common (1860). 



b 



a. Trail. 



b. Boulder-clay not seen in pit, but showing a short distance higher up on 



the hill. 



c. White sand, with seams of flint and white quartz-pebbles (Westleton). 



d. Laminated ferruginous and yellow sands, ochi-eous and ferruginous sands. 



Speaking of this district, Mr. Whitaker notices " a deposit of 

 less certain classification which has been mapped only over the 

 small tract north of the Minsmere Level. This is a gravel, with 

 occasional sand, composed for the most part of pebbles (chiefly of 

 flint, but some of quartz) ; and whilst it seems to underlie the 

 lowest beds of the Glacial Drift, rests generally irregularly on the 



* 'A Sketch of the History of the Eivers and Denudation of West Kent,' 1880. 

 t Excepting the extreme N.W. corner and Hertford Heath. 

 I Geology of the N.W. part of Essex and the N.E. part of Herts, with parts 

 of Cambridgeshire and Suffolk, 1878. 



