INTRODUCTION. xv 



not actually coeval with the Upper Crag beds themselves, they must have followed directly 

 upon the elevation of the Chillesford clay into land. 



With respect to beds D and E a different case presents itself. There occurs at the 

 foot of the lighthouse ravine of Kessingland Cliff, a bed of micaceous clayey sand, which 

 is marked in Section T as £?. So far as occasional clearances of the talus after storms 

 has permitted Mr. Crowfoot (who has watched the section for some years) to see, the root- 

 indented mottled clay D, with the freshwater bed E in its hollow, appears to lie up to 

 this micaceous clayey sand, in the way shown in Section T. If this be so, and the bed 

 S? be the Chillesford clay, then these beds, D and E, are posterior to the Crag. Even 

 then, however, it by no means follows that D and E are coeval with A, B, and C, because, 

 while the latter are overlain by the pebbly sand (6) and the other beds of the Lower 

 Glacial series, the Middle Glacial (8) alone, as far as the talus allows us to see, rests 

 upon D and E in the Kessingland section. As, therefore, the Lower Glacial beds are 

 proved by outliers still remaining to the south (those of the pebbly sands being extensive) 

 to have once overspread Kessingland, we cannot resist the conclusion that beds D and 

 E, if coeval with A, B, and C, must have been covered by these Lower Glacial beds ; 

 and these, latter, to have been so exactly denuded prior to the Middle Glacial sands, as 

 to have left the root-penetrated surface of the clay D intact, (as it may now be seen 

 to exist, along a section of near a mile in extent) and yet have cleared away every 

 trace of the Lower Glacial beds. All, therefore, that can safely be averred of beds A, 

 B, and C is, that they are anterior to the Lower Glacial ; and of beds D and E, that they 

 are anterior to the Middle Glacial, and probably posterior to the Crag. 



The Lower Glacial Series (Nos. 6 and 7). 



The beds of this series (6, 6a, and 7) are shown in Sections C, D, E, P, G, H, J, K, 

 L, M, N, 0, R, S, U, and W. The lowest, the pebbly sands, 6, 1 consist of sands, mostly of a 



1 These sands were first brought to the notice of geologists by one of us under the name of " Bure 

 Valley beds," and their range from the Bure Valley past Norwich to the neighbourhood of Southwold, as 

 well as their inferiority to the contorted drift, and their superiority to the Chillesford clay, was shown by 

 diagram and numerous vertical sections. This was in 1866 (see ' Quart. Jour. Geol. Soc.,' vol. xxii, p. 546). 

 Their position, and that of the formations Nos. 1, 4, 5, 7, 8, 9, and 10, both above and below Norwich, 

 will be found again represented in sections in the journal for the same year by the other of us, precisely as 

 they are in that neighbourhood in the present sections (see vol. xxiii, p. 89). In 1868 the structure of 

 Norfolk and Suffolk, illustrated by map and copious sections, was laid by us before the British Association 

 in the same way in which it is represented in the present map and sections, with the exception that the 

 identity of the pebbly sand of Weybourn which underlies the Cromer Till along the North Norfolk 

 coast, with the Bure Valley beds, was expressly left open for further investigation ; it being pointed out 

 that the Weybourn sand and the overlying Cromer Till (with the base of which it is interbedded) occupied, 

 relatively to the contorted drift, the same position as did the Bure Valley beds ; so that they might either 

 be the equivalent of these Bure Valley beds, or be a formation subsequent to them, and intervening between 



