388 S. V. Wood , jun., 4 ' F. W. Harmer — The Kessingland Bed. 
posing that we have referred to it as a peculiarly Arctic shell. If he 
liad remembered that it is found now living everywhere on the 
Norfolk coast, he would hardly have attributed to us such exceptional 
simplicity. What we have contended is that this shell, which is 
Arctic as well as West European, has not occurred in any bed of 
Crag age, notwithstanding various assertions to the contrary ; and 
that therefore as it does occur (and always in abundance) in every 
fossiliferous marine bed of newer age than the Crag, it furnishes a 
clear palseontological horizon by which to divide the Crag from beds 
of Glacial age. With the exception of Turritella terebra, Pleurotoma 
turricula, Ostrea edulis, and a species of Lacuna, 1 all the marine 
shells mentioned by Mr. Eeid as discovered by him in these Wey- 
bourne sands will be found in the Lower Glacial column of the 
tabular list in the “ Supplement to the Crag Mollusca,” or in the 
additions thereto given in the note to our joint paper in the Quarterly 
Journal of the Geological Society for February, 1877 ; and it is satis- 
factory to us to find, by the few additions only which have resulted 
from Mr. Reid’s lengthened stay upon and study of this coast, that 
we had so nearly arrived, by our own researches, at the molluscan 
fauna of these Lower Glacial sands. 
Lastly. If we understand Mr. Reid’s paper aright, he thinks that 
the beds between the Chalk and the Till on the coast constitute only 
one formation, and that such formation is an estuarine one. This is 
what we have always contended, only we add to it that this forma- 
tion is the same as the pebbly sands described by one of us in 1866, 
linder the name of “ Bure Valley beds,” and afterwards by Prof. 
Prestwich in 1870 under the name of “ Westleton Shingle;” 2 and 
also that the Till is merely a continuation of the same deposit, due to 
increasing depth of water combined with glacial action ; and this is 
one of the very few things connected with the Glacial beds as to which 
we feel no doubt. If the pebbly sands thus characterized by Tellina 
Balthica, which form the base of the Cromer Till (or Lower Boulder- 
clay of Mr. Reid and others), are to be rejected from the Glacial 
formation, to which, although they may present no indications of 
glacial action, they structurally belong, because their marine fauna 
is not, as is the fact, more Arctic than the uppermost beds of the 
Crag (though both contain several species of mollusca that now live 
only in Arctic seas), tlien most assuredly the sands and gravels 
which we term Middle Glacial should be rejected also from the 
Glacial formation, because their molluscan fauna is even less Arctic 
1 The Car di um Grocnlandicum of Mr. Reid is no doubt the shell given in the tabular 
list which accompanies the “ Supplement to the Crag Mollusca,” as Cardium Island- 
icwn with a ? These imperfect decorticated specimens of Cardium cannot be identified 
with any certainty. 
2 Jt is not our business to defend Prof. Prestwich’s identification of the sbingle at 
Westleton with these Weybourne sands, which the gentlemen of the Survey impugn; 
but with respect to the identity which they discover between that shingle and the 
mass which plunges into the Middle Glacial sand of Dunwich cliff, we heg to say 
that this shingle (gravel) was several years ago, when that cliff could be ascended at 
the spot, and closely examined, divided at one end from the Middle Glacial sand 
beneath it by a denuded remnant of the Upper Glacial clay, in the manner shown in 
Section R, which accompanies the map in tbe “ Supplement to the Crag Mollusca,” 
and perhaps this remnant may still be found if looked for. 
