xvi SUPPLEMENT TO THE CRAG MOLLUSCA. 



deep orange colour, more or less interbeclded with seams of rolled pebbles. The pebbles in 

 some places so predominate as to form masses of shingle, while near their southern extremity, 

 in the immediate neighbourhood of Halesworth (Section G) and of Henham (see northern 

 end of Section C), they appear in the form of true beaches, as already mentioned at page vi. 

 These sands and pebble beds contain shell fragments occasionally, but recognisable fossils 

 only at Crostwick, Rackheath, Spixworth, Wroxham, and Belaugh inland, and along the 

 coast at Weybourn, between that place and Runton, and about Trimmingham. They form 

 the base of the whole Glacial series, and indicate the first setting in of the great Glacial 

 subsidence. While their pebbles and shingle thus indicate shore conditions, their fauna 

 is as truly Fluvio-marine as the beds 4 and 5' ; and while in some parts, as in Sections 

 D, E (at Ingate), (at Hartford Bridges), S, VIII, IX, X, XT, XII, and XV, they rest on 

 and more or less indent the Chillesford clay; in others, as in Section G, they occupy its 

 place, lying in the beached form up against foreshores of this clay. 1 



Their fauna has been investigated with some perseverance, but it is well worth further 

 research. So far as yet known, it differs from that of the Fluvio-marine Crag and Chilles- 

 ford beds in the disappearance, or in the increasing rarity of certain forms, rather than in 

 the introduction of new ones. Of the three specially common species of Tellina charac- 

 teristic of the Chillesford beds, T. obliqua, T. lata, and T. pratenuis, the latter is, in these 



them and the contorted drift. (See abridgment of the paper in 'Geological Magazine,' vol. v, p. 452.) 

 Having, soon after this, satisfied ourselves that they actually were such equivalent, we took the opportunity 

 of laying a section disclosed by the Norwich Sewer Works before the Geological Society, in April, 1869, to 

 assert this; and at page 446 of vol. xxv of their journal the succession of the beds about Norwich is once 

 more shown in section ; and the pebbly sands (Bare Valley beds), which in that section are shown as 

 succeeding the Chillesford clay, are expressly stated to "expand northwards into the Weybourn sand and 

 Boulder Till of the Cromer Cliff section, to he unconformable to the Crag and Chillesford beds, to be 

 palaeontologically distinct from them, and to be characterised by the first appearance in England of Tellina 

 Balthica." In the 'Geological Magazine' for January, 18/0 (pp. 19, 20, and 21), this position of the 

 pebbly sands and Cromer Till was again pointed out very distinctly, and the character of the fauna which 

 had been obtained by us from those sands at Belaugh, Rackheath, Weybourn. and Runton (Woman Hythe), 

 explained. Lastly, in the same magazine for September, 1871, a woodcut of the coast section from Cromer 

 to Woman Hythe is given exactly as in the present Section W. Subsequently to all this Mr. Prestwich, 

 in the 'Quarterly Journal of the Geological Society' for November, 1871, brings forward this pebbly sand 

 as something new, assigning to it the name of " Westleton Shingle" ; and, apparently overlooking much 

 of what had been thus brought forward by us, altogether misrepresents our views as thus matured, basing 

 them apparently on the paper of 1866. Hence the above explanation. We have, under these circum- 

 stances, here refrained from assigning any other name to these sands than that of "pebbly" to denote 

 their character; but if a local name be desirable, none can be so proper as that of " Bure Valley beds," 

 both by reason of its priority, and of the fact that their greatest exposure, and their principal fossiliferous 

 localities, occur in the valleys of the Bure and its tributaries. 



1 Some of the patches of Chillesford beds shown underlying the pebbly sands in Sections N and are, of 

 course, merely hypothetical, and are inserted under the mass of newer beds only to show the patchy way 

 in which they remain wherever the chalk floor is exposed. 



