XVI SUPPLEMENT TO THE CRAG MOLLUSCA. 
deep orange colour, more or less interbedded 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), O (at Hartford Bridges), S, VIII, IX, X, XI, XII, and XV, they rest on 
and more or less indent the Chillesford clay; in others, as in Section G, they oceupy its 
place, lying 2 the beached form up against foreshores of this clay." 
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 Ze/lina charac- 
teristic of the Chillesford beds, 7. obliqua, T. lata, and T. pretenuis, 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 (Bure 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 be unconformable to the Crag and Chillesford beds, to be 
paleeontologically distinct from them, and to be characterised by the first appearance in England of Tedlina 
Balthica.” In the ‘Geological Magazine’ for January, 1870 (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 Oare, 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. 
