Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/765

 proboscidean remains, and an opening is made for the Forest-bed between them.

It might be supposed to be easy to trace the Fluvio-marine Crag to the coast-section, and so to prove whether it dips beneath the Forest-bed or whether it overlies it and is identical with the Fluvio-marine of the coast-section ; but much difficulty arises from the Fluvio-marine crag inland being cut off and intercepted by the valleys of the Bure and of the Wensum, and several of their tributaries : and this difficulty appears to be increased by a slight upheaval of the chalk to the west of those rivers. This may be seen by the elevation of the Chillesford clay at Bramerton about 15 feet above its level at the Brundall Station ; and the same may be noticed at Horstead and Wroxham, on the west side of the Bure, and at Hoveton St. John, on the east side.

On full consideration, I am inclined to the opinion that the Fluvio-marine and the Marine crags of the inland section are identical with those on the coast. The freshwater beds in the coast- section, which are absent inland, impress me with the correctness of this view of the case, because they seem to have been laid down at a lower level on the first going down of the Forest-bed; and then, when the level was obtained, the Fluvio-marine beds were spread over the freshwater beds and over the extended area of the chalk, which was covered with the bed of stones ; and then, in like manner, the Marine beds were laid down, including the Chillesford clay, which is admitted to be the same in both sections.

The correspondence and junction of the several beds at both extremities of the Forest-bed are almost conclusive in favour of their identity.

On the other hand, the greater variety and quantity of mollusks in the Fluvio-marine and Marine crags of the inland sections may be regarded as evidence against their identity j but such an accumulation of shells may be expected near the strike of the beds, where the water was more shallow than at a distance from the margin of the chalk *.

I trust that the above observations respecting the stony bed upon the chalk, if not conclusive, may prove of service in determining the relative ages and positions of the Forest- and other beds.

Discussion.

Sir Charles Lyell considered the Forest-bed to be newer than the stony bed.

Mr. Gunn remarked that at Easton Bavent the Chillesford Clay is in the cliff, and the Forest-bed in the beach beneath it. He referred to various instances of the occurrence of mammalian remains on the coast beneath the Chillesford Clay, whereas he had never found any above it.

in great abundance near Sherringham, beneath the Chillesford clay, and as low as the stony bed; but the introduction of these shells may be attributed to northerly currents of water.
 * A fresh complication has arisen from the discovery of the Tellina balthica

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