Notices of Memoirs — Prof. Prestwich on Mimdesley Beds. 467 



little above the sea-level, resting everywhere on an undisturbed or 

 very slightly eroded bed of Chillesford Clay, and being succeeded, 

 with but slight evidence of denudation, by the Lower Boulder-clay, 

 or by the Glacial sands and gravel ; whereas, as it trends inland, it 

 attains a considerable elevation above the sea-level, passes uncon- 

 formably over the older Tertiary strata, and has been subjected 

 to a great amount of denudation. On the other hand, the old laud 

 which seems to have extended from the eastward as far as the 

 Norfolk coast, is now in great part below the level of the German 

 Ocean. Further, whereas the succeeding Glacial beds all show a 

 drift from northward to southward, this is the only case that has 

 come under the author's notice of a marine drift from southward to 

 the northward. 



The Westleton Beds, in their more typical aspect, consist of 

 quartzose sands full of flint pebbles, almost as much worn and as 

 numerous as in the Lower Tertiary sands of Addington. With these 

 are mixed — (1) A good many small white and rose-coloured quartz- 

 pebbles ; (2) Pebbles of Lydian stone ; (3) Large flattened pebbles 

 of a light-coloured quartzite; and (4) Eolled and worn fragments 

 of Lower Greensand chert. It is the presence of these, and espe- 

 cially of the last, that constitutes so marked a feature of these beds, 

 and which, with the absence of pebbles and rock-fragments of 

 northern origin, serve to separate them from the Inter-glacial sands 

 and shingle with which in places they come into juxtaposition. 



The author then proceeds to trace the beds through Essex, and 

 gives a series of railway sections showing these beds, exhibiting 

 usually the appearance of a white gravel, with intercalated ochreous 

 beds, and reposing on a very eroded surface of the London Clay. 

 Near Clare there is a pit in which they exhibit oblique lamination, 

 and might, apart from the want of fossils, be mistaken for a Crag 

 section. Near Braintree, a remarkable section was exposed in the 

 branch railway to that town. It showed these beds much faulted, 

 overlaid irregularly by a darker bed full of New Eed Sandstone 

 quartzite pebbles, and the whole covered by indenting Boulder-clay. 



In traversing the beds farther westward they undergo further 

 modification. Certain characters remain, however, persistent, and 

 on these we have to rely. 1st, the shingle is composed essentially 

 of chalk-flint pebbles, becoming less worn as we approach the 

 southern limits of the deposit ; 2ndly, it often becomes much mixed 

 with flint-pebbles and subangular fragments of compact sandstone 

 derived from the underlying Tertiary strata ; Srdly, the chert and 

 raa'stone fraffments often so increase in numbers as to constitute a 

 large portion of the gravel. They are worn and subangular, and the 

 chert is identical with the chert of the Lower Greensand of Kent and 

 Surrey ; 4thly, the pebbles of white and rose-coloured quartz, of 

 Lydian stone, and of white quartzite become rarer, and in places are 

 wanting. The Lydian stone and some of the small quartz pebbles 

 may be derived, with the chert, from the Lower Greensand, but this 

 will not account for the great number of quartz pebbles found in tlie 

 Eastern Counties. The quartzite pebbles are equally large but 



