CEOMER FOREST-BED. 
175 
in these strata, and it is still somewhat uncertain to which horizon 
they may belong. They may form part of the Forest-bed series, 
or of the Leda-myalis Bed, or may be considerably newer. 
Beneath these pebbly sands there is sometimes a thin layer of 
much compressed lignite, resting directly on the old land- 
surface or '' Rootlet-bed,” and apparently intimately connected 
with it. Then comes the Rootlet-bed, which “consists of a 
greenish and dark bluish-grey unstratified clay, with occasional 
white calcareous concretions (“ race ”) and ferruginous sandy con¬ 
cretions, and it contains mammalian remains . . , Thousands 
of rootlets may be seen here, at times, penetrating the bed 
vertically as they grew . . . . They vary from about J incli 
to 1-| inch in thickness at the surface and gradually taper away 
to nothing, as at Kessingland and Pakefield; all are more or less 
crumpled, similar in appearance, and only occasionally forked.”'^ 
The roots are similar to those of pine, but those which I 
examined were not sufficiently well preserved definitely to show 
coniferous structure under the microscope, and all we can say 
is that they belong to some exogenous tree. 
The strata below the Rootlet-bed are very seldom exposed, 
bub in one spot Mr. Blake observed about three feet of stratified 
grey and brown clay and brown sand, and in three of the 
borings made by the Geological Survey gravels with quartzite 
pebbles were met with—as was the case near Happisburgh. 
The gravel was so loose and full of water that none of the 
borings at Gorton could be carried to its base; the thickness of 
the Forest-bed series, and the nature of the underlying deposits 
are therefore still unknown. 
At the point where the Pliocene strata first rise above the 
beach, and for 200 yards further south, the clayey Rootlet- 
bed is immediately overlain by Boulder Clay. This absence 
of any pervious beds has led to the preservation of calcareous 
fossils, so that here, and here only on this part of the coast, 
are mollusca found in the Rootlet-bed. By far the commonest 
species is Helix hispida, but Mr. Blake also records Bythinia 
tentacvdata, Limncea stagnalis, Planorhis corneus, P. spirorbis, 
Succinea putris, Valvata piscinalis, and a Unio or Anodon. 
Mammalian bones also occur in the deposit. 
A trial-boring further south, about midway between the two 
outliers of Chalky Boulder Clay, was interesting as showing the 
character of the Rootlet-bed at a spot where all shells have dis¬ 
appeared. This boring also proved the nature of the underlying 
deposit, which there is little doubt should also be referred to 
the Forest-bed series:— 
Feet. 
Forest-bed 
Series. 
Ferruginous gravel with quartz and quartz- 
[ ite - 
* J. II. Blake, Geology of Yarmouth and Lowestoft. {Memoirs of Lhe Geological 
Survey'), p. 20. 
