(FIGURE 27. DIAGRAM TO ILLUSTRATE THE GENERAL SUCCESSION
OF THE STRATA IN THE NORFOLK CLIFFS, EXTENDING SEVERAL MILES
NORTH-WEST AND SOUTH-EAST OF CROMER.
A. Site of Cromer Jetty.
1. Upper Chalk with flints in regular stratification.
2. Norwich Crag, rising from low water at Cromer to the top
of the cliffs at Weybourn, seven miles distant.
3. "Forest Bed," with stumps of trees in situ and remains of
Elephas meridionalis, E. primigenius, E. antiquus, Rhinoceros
etruscus, etc. This bed increases in depth and thickness
eastward. No Crag (Number 2) known east of Cromer Jetty.
3 prime. Fluvio-marine series. At Cromer and eastward, with
abundant lignite beds and mammalian remains, and with cones
of the Scotch and spruce firs and wood. At Runton, north-west
of Cromer, expanding into a thick freshwater deposit, with
overlying marine strata, elsewhere consisting of alternating
sands and clays, tranquilly deposited, some with marine,
others with freshwater shells.
4. Boulder clay of glacial period, with far transported erratics,
some of them polished and scratched, 20 to 80 feet in thickness.
5. Contorted drift.
6. Superficial gravel and sand with covering of vegetable soil.)
The annexed section (Figure 27) will give a general idea of the ordinary succession of the Pliocene and Pleistocene strata which rest upon the Chalk in the Norfolk and Suffolk cliffs. These cliffs vary in height from fifty to above three hundred feet. At the north-western extremity of the section at Weybourn (beyond the limits of the annexed diagram), and from thence to Cromer, a distance of 7 miles, the Norwich Crag, a marine deposit, reposes immediately upon the Chalk. A vast majority of its shells are of living species such as Cardium edule, Cyprina islandica, Scalaria groenlandica, and Fusus antiquus, and some few extinct, as Tellina obliqua, and Nucula Cobboldiae. At Cromer jetty this formation thins out, as expressed in the diagram at A; and to the south we find Number 3, or what is commonly called the "Forest Bed," reposing immediately upon the Chalk, and occupying, as it were, the place previously held by the marine Crag Number 2. This buried forest has been traced for more than 40 miles, being exposed at certain seasons and states of the beach between high and low water mark. It extends from Cromer to near Kessingland, and consists of the stumps of numerous trees standing erect, with their roots attached to them, and penetrating in all directions into the loam or ancient vegetable soil on which they grew. They mark the site of a forest which existed there for a long time, since, besides the erect trunks of trees, some of them 2 and 3 feet in diameter, there is a vast accumulation of vegetable matter in the immediately overlying clays. Thirty years ago, when I first examined this bed, I saw many trees, with their roots in the old soil, laid open at the base of the cliff near Happisburgh; and long before my visit, other observers, and among them the late Mr. J.C. Taylor, had noticed the buried forest. Of late years it has been repeatedly seen at many points by Mr. Gunn, and, after the great storms of the autumn of 1861, by Mr. King. In order to expose the stumps to view, a vast body of sand and shingle must be cleared away by the force of the waves. [Note 21]
As the sea is always gaining on the land, new sets of trees are brought to light from time to time, so that the breadth as well as length of the area of ancient forest land seems to have been considerable. Next above Number 3, we find a series of sands and clays with lignite (Number 3 prime), sometimes 10 feet thick, and containing alternations of fluviatile and marine strata, implying that the old forest land, which may at first have been considerably elevated above the level of the sea, had sunk down so as to be occasionally overflowed by a river, and at other times by the salt waters of an estuary. There were probably several oscillations of level which assisted in bringing about these changes, during which trees were often uprooted and laid prostrate, giving rise to layers of lignite. Occasionally marshes were formed and peaty matter accumulated, after which salt water again predominated, so that species of Mytilus, Mya, Leda, and other marine genera, lived in the same area where the Unio, Cyclas, and Paludina had flourished for a time. That the marine shells lived and died on the spot, and were not thrown up by the waves during a storm, is proved, as Mr. King has remarked, by the fact that at West Runton, north-west of Cromer, the Mya truncata and Leda myalis are found with both valves united and erect in the loam, all with their posterior or siphuncular extremities uppermost. This attitude affords as good evidence to the conchologist that those mollusca lived and died on the spot as the upright position of the trees proves to the botanist that there was a forest over the Chalk east of Cromer.
Between the stumps of the buried forest, and in the lignite above them, are many well-preserved cones of the Scotch and spruce firs, Pinus sylvestris, and Pinus abies. The specific names of these fossils were determined for me in 1840, by a botanist of no less authority than the late Robert Brown; and Professor Heer has lately examined a large collection from the same stratum, and recognised among the cones of the spruce some which had only the central part or axis remaining, the rest having been bitten off, precisely in the same manner as when in our woods the squirrel has been feeding on the seeds. There is also in the forest-bed a great quantity of resin in lumps, resembling that gathered for use, according to Professor Heer, in Switzerland, from beneath spruce firs.
The following is a list of some of the plants and seeds which were collected by the Reverend S.W. King, in 1861, from the forest bed at Happisburgh, and named by Professor Heer:—
PLANTS AND SEEDS OF THE FOREST AND LIGNITE BEDS BELOW THE GLACIAL DRIFT OF THE NORFOLK CLIFFS.
Pinus sylvestris, Scotch fir.
Pinus abies, spruce fir.
Taxus baccata, yew.
Nuphar luteum, yellow water-lily.
Ceratophyllum demersum, hornwort.
Potamogeton, pondweed.
Prunus spinosus, common sloe.
Menyanthes trifoliata, buckbean.
Nymphaea alba, white water-lily.
Alnus, alder.
Quercus, oak.
Betula, birch.
The insects, so far as they are known, including several species of Donacia, are, like the plants and freshwater shells, of living species. It may be remarked, however, that the Scotch fir has been confined in historical times to the northern parts of the British Isles, and the spruce fir is nowhere indigenous in Great Britain. The other plants are such as might now be found in Norfolk, and many of them indicate fenny or marshy ground.*