(FIGURE 33. SECTION OF THE NEWER FRESHWATER FORMATION I
N THE CLIFFS AT MUNDESLEY, EIGHT MILES SOUTH-EAST OF CROMER,
DRAWN UP BY THE REVEREND S.W. KING.
Height of cliff where lowest, 35 feet above high water.
OLDER SERIES.
1. Fundamental Chalk, below the beach line.
3. Forest bed, with elephant, rhinoceros, stag, etc., and with
tree roots and stumps, also below the beach line.
3 prime. Finely laminated sands and clays, with thin layer of
lignite, and shells of Cyclas and Valvata, and with Mytilus
in some beds.
4. Glacial boulder till.
5. Contorted drift.
6. Gravel overlying contorted drift.
N.B.—Number 2 of the section, Figure 27, is wanting here.
NEWER FRESHWATER BEDS.
A. Coarse river gravel, with shells of Anodon, Valvata, Cyclas,
Succinea, Limnaea, Paludina, etc., seeds of Ceratophyllum
demersum, Nuphar lutea, scales and bones of pike, perch,
salmon, etc., elytra of Donacia, Copris, Harpalus,
and other beetles.
C. Yellow sands.
D. Drift gravel.)
When I examined this line of coast in 1839, the section alluded to was not so clearly laid open to view as it has been of late years, and finding at that period not a few of the fossils in the lignite beds Number 3 prime above the forest bed, identical in species with those from the post-glacial deposits B C, I supposed the whole to have been of contemporaneous origin, and so described them in my paper on the Norfolk cliffs.*
(* "Philosophical Magazine" volume 16 1840 page 345.)
Mr. Gunn was the first to perceive this mistake, which he explained to me on the spot when I revisited Mundesley in the autumn of 1859 in company with Dr. Hooker and Mr. King. The last-named geologist has had the kindness to draw up for me the annexed diagram (Figure 33) of the various beds which he has recently studied in detail.*
(* Mr. Prestwich has given a correct account of this section
in a paper read to the British Association, Oxford, 1860.
See "The Geologist" volume 4 1861.)
The formations 3, 4, and 5 already described, Figure 27, were evidently once continuous, for they may be followed for miles north-west and south-east without a break, and always in the same order. A valley or river channel was cut through them, probably during the gradual upheaval of the country, and the hollow became afterwards the receptacle of the comparatively modern freshwater beds A, B, C, and D. They may well represent a silted up river-channel, which remained for a time in the state of a lake or mere, and in which the black peaty mass B accumulated by a very slow growth over the gravel of the river-bed A. In B we find remains of some of the same plants which were enumerated as common in the ancient lignite in 3 prime, such as the yellow water-lily and hornwort, together with some freshwater shells which occur in the same fluvio-marine series 3 prime.
(FIGURE 34. Paludina marginata, Michaud (P. minuta, Strickland).
Hydrobia marginata.*
(* This shell is said to have a sub-spiral operculum (not a
concentric one, as in Paludina), and therefore to be
referable to the Hydrobia, a sub-genus of Rissoa. But
this species is always associated with freshwater shells,
while the Rissoae frequent marine and brackish waters.)
The middle figure is of the natural size.)