196 
DEPOSITS OP DOUBTFUL AGE. 
water deposits at Beeston do not really represent the Leda- 
myalis Bed. It seems probable that the succession published in 
1880* is the correct one, for the fossiliferous Arctic Freshwater 
Bed can always be traced continuously upwards, till cut off by 
the Boulder Olay. The two seams undoubtedly belonging to 
the Leda-myalis Bed both lie some distance below the Boulder 
Clay and rest on Pliocene Beds. No arctic plants have, however, 
yet been found directly over the marine beds at West Bunton 
or Sherringhain. The age of the unfossiliferous sands and 
gravels which, at these localities, separate the marine bed from 
the Boulder Clay, is therefore still uncertain. 
No other locality for the arctic plants is at present known 
west of Cromer. Several of the loams at Beeston and Sher- 
ringham have a rather weathered appearance, and seem to 
have been penetrated by small roots, such as might belong to 
the dwarf birches and willows. This evidence of ancient land- 
surfaces is thoroughly in keeping with the amphibious character 
of the mollusca, which remind one much of those of the loess 
of the Rhine, the land forms being only such as ordinarily live on 
alluvium, and can survive submergence for a limited time, while 
the freshwater species can live in damp mud. The species found 
were Succinea putris, S. ohlonga, Helix hispida'^. Valvata 
piscinalis, and Pisidium henslowianum. 
Though it is probable that further search may lead to the 
discovery of localities for the Arctic Freshwater Bed near 
Cromer, at present there is an interval of about nine miles 
to the next exposure. This was found nearly a mile west of 
Mundesley, where the section shown in Fig. 40, p. 166, was 
exposed about the year 1876. 
In the Cromer Memoir beds 3 and 4 were referred to the 
Forest-bed Series, but at that time the plants had not been 
examined, the specimens having miscarried. It is now found 
that among them are leaves of Salix polaris and Betula ncma, 
proving that the deposit belongs to the Arctic Freshwater Bed. 
From this point eastward to Mundesley the Arctic Freshwater 
Bed appears to be continuous, though only sparingly fossiliferous. 
A short distance north-west of Mundesley, in the original section 
discovered by Prof. Nathorst, the details vary continually, but 
at one of the most fossiliferous spots, immediate!}^ under the rain¬ 
water spout between the Coast Guard Station and the road to 
the Manor House, the following series of deposits occurs :— 
Feet. 
9 T'll / Boulder Clay, full of chalk. 
^ ^ t Hard blue loam and a little sand - - 3 
rStiff blue clay with moss, Hip^puris vulgaris, 
Salix polaris, elytra of beetles, Succineaputris, 
Arctic Fresh- J S. ohlonga. Pupa muscorum, and bones of 
water Bed. Spermophilus - - - - 
I Sand and blue loam, contorted together ; fresh- 
h water shells, Pisidium amnicum ? 
Geol. Mag., dec. II., vol. vii., p. 548. 
