CKOMER FOREST-BED. 
173 
350 yards farther, it is seen at the foot of the beach, and can be 
followed to within a quarter of a mile of the Low Lighthouse; 
but its lithological character is peculiar, and does not clearly in¬ 
dicate to which division the strata here exposed belong. The 
deposit consists of carbonaceous silt, full of small pieces of wood, 
and occasional fir-cones, passing laterally into hard blue-black 
carbonaceous clay with earthy ferruginous concretions containing 
scattered twigs. 
This is the last exposure of the Forest-bed visible north of 
Yarmouth, for a few yards further the base of the Boulder Clay 
sinks below low-water mark. The Forest-bed mentioned by 
several authors as occurring at Eccles and Palling is undoubtedly 
a recent deposit, for it can be seeii to rest on Boulder Clay. 
Though so little of the Forest-bed lies above the sea-level south 
of Happisburgh, there is evidently a considerable thickness below ; 
for after the storm of January 30th, 1877, large slabs of fresh¬ 
water clay-ironstone, and pan were thrown up on the beach at 
Happisburgh and Eccles. These slabs were full of impressions 
of leaves of oak, elm, beech, birch, and willow ; they contained 
seeds of the bog-bean, and casts of Unio ^pictorvjm^ Pisidium, 
Pahulina, Limncea, and a species of fish, probably the roach. 
Fragments of this fossiliferous ironstone, which a|)pears to 
represent the Lower Freshwater Bed, occur in the estuarine 
gravels of the Forest-bed. 
As, from the size and angularity of the slabs, the ironstone 
was evidently in place under the sea at Happisburgh, it was 
dragged for from a boat during the progress of the Geological 
Survey. At half-a-mile north-north-east of the Low Light¬ 
house we found a rocky bottom at 10 fathoms; and as the boat 
drifted further out the lead swung off what appeared to be a 
submarine cliff, and dropped into 15^ fathoms, the arming 
showing sand with black specks in this hollow. We then tried 
to detach slabs of the rock with grappling irons, but after twice 
getting them fixed we had to abandon the attempt. The teeth 
of the irons were bent by the strain, and had evidently played 
against a fine-grained tough ferruginous rock, like the slabs 
found on the beach. Six weeks later another attempt was made 
to examine this ironstone, but where previously there had been 
a depth of 10 or 15 fathoms, there was now only at most 6 J. The 
presence of sandbanks near the shore causes the tide to flow 
in regular channels, which, during gales, are scoured to a great 
depth, only to be again filled up. In this way submarine denu¬ 
dation perhaps proceeds at depths considerably greater than in 
the open sea. 
There is no evidence as to the full thickness of the Forest-bed at 
Happisburgh, bub it seems to extend from high-water to at least 
10 fathoms below low-water (including the ironstone), which 
would make it over 70 feet. From the occurrence of the sub¬ 
marine cliff mentioned above, it is clear that the ironstone rests 
not on Chalk but on soft beds, which descend to at least 
