620 REPORT — 1881. 



2. On the Strata, hetiveen the Ghillesford Beds and, the Lower Boulder Glay^ 

 ' The Mundesley and Westleton Beds.'' Bij Professor J. Prestwich^ 

 M.A., F.B.8., 



Where a particulai" series of strata presents, in adjacent and conterminous areas,, 

 markedly different palaeontological and lithological characters, it may be sometimes- 

 convenient, as in the case of the ' Reading- and Woolwich Series,' to give them a 

 double geographical term, indicative of the localities where each type is well- 

 developed, and its relation to the overlying and underlying strata well shown. 



The beds between the Ghillesford Clay and the Lower Boulder Clay present 

 such a series. Its exhibition on the coast of Norfolk, although very limited, is- 

 accompanied by special palaeontological features, that have caused it to be divided 

 into the number of local beds which have been described by Trimmer, Green,, 

 Gunn, Wood, and Havmer, the author, Reid, Blake, and others. It includes the 

 ' Laminated Clays,' the ' Elephant ' and ' Forest beds ' of Gunn, the ' Bure Valley 

 Crag ' of S. Wood, the ' Westleton Shingle ' of the author, and the ' Rootlet-bed ' 

 of Blake. Without reverting at present to the exact correlation of the several 

 beds in the Norfolk area, respecting which there is still some difference of opinion, 

 the author suggests that they should all be included under a general term founded 

 on the localities where, on the one hand, their varied paheontological characters are 

 exhibited, and on the other, where their peculiar lithological characters are well- 

 marked — characters which the author proposes to show, in another paper, have a 

 very wide range, and serve to mark an important geological horizon affecting some 

 interesting questions of local physical geology. 



The Mundesley beds were described by the author in 1860, and consist of 

 alternating beds of clay, sands, and shingle, some containing freshwater and othera 

 marine mollusca, with a forest-growth and mammalian remains at their base ; 

 and again in 1871, when he included them in his Westleton group (No. 5 of his 

 sections), which he showed at that place to consist entirely' of great masses of 

 well-rounded shingle, with intercalated seams containing traces only of marine- 

 shells. Seeing the inconvenience of attaching the same term to the two very 

 distinct series of beds, and that it may conflict with other local terms, the author 

 now proposes to group this series under the term of ' The Mundesley and Westle- 

 ton Beds,' indicative of their stratigraphical position in Norfolk, and of characters 

 in Suffolk which serve to identify them in their range westward and inland to 

 considerable distances beyond the Crag area. At the same time, it maybe conve- 

 nient, for brevity, to use one term only in speaking of typical cases. 



3. On the Extension into Essex, Middlesex, and other Inland Counties, of the 

 Mundesley and Westleton Beds, in relation to the age of certain hill- 

 gravels and of some of the valleys of the Souf/i, of England. By 

 Professor J. Prestwich, M.A., F.B.8. 



The author gives in this paper the result of observations commenced more than 

 30 years since, but delayed publication partly in consequence of the complexity 

 of some of the phenomena. As mentioned in the preceding paper, a peculiar 

 group of land, freshwater, and marine beds occupy, on the Norfolk coast, a zone 

 between the Ghillesford Clay and the Lower Boulder Clay. As we proceed south- 

 ward, the land and freshwater conditions are gradually eliminated, and marine- 

 conditions there alone prevail. Poorly marked as the marine evidence is in Suffolk, 

 this evidence is entirely wanting further inland, and we have only levels, super- 

 position, and structure to rely on in correlating the fragmentary outliers into which 

 these beds finally resolve themselves. Again on the coast of the Eastern counties, 

 this group forms a nearly level plane but little above the sea-level, resting every- 

 where on an undisturbed or very slightly eroded bed of Ghillesford 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 



