CROMER FOREST-BED. 
185 
The land shells of the Forest-bed are exclusively those found on 
alluvium or in wet moss. There is not a single representative of 
the numerous species confined to dry or calcareous soils. 
Plants in the British Pliocene deposits are only known from 
the Cromer Forest-bed. As there is also no other Upper Pliocene 
flora of any extent yet discovered in Northern Europe, it is 
impossible to compare the floras of the different horizons. From 
the Forest-bed 56 species of flowering plants have now been 
determined. Two of them—the water chestnut and the spruce 
fir—do not appear to have belonged to our flora since the 
Glacial Epoch ; the others are nearly all still living in Norfolk. 
There is also a considerable number of seeds still undetermined, 
and at least two of these seem to belong to no living British 
plant. 
As evidence of the climatic conditions which prevailed during 
this period, the first place must be given to the flora. The 
slow rate of change, which renders plants so untrustworthy in 
settling questions of geological classification, gives them the 
highest value when we inquire into former climatic conditions. 
Plants are also, as a general rule, more directly affected than 
animals by changes of temperature and rainfall. 
The flora contained in the Cromer Forest-bed may be divided 
into two groups ; the forest-trees, and the marsh and aquatic 
plants. Of the upland plants, and of the plants of dry or chalky 
soils we at present know absolutely nothing. The forest-trees 
are well represented—in fact they are better known than in any 
of our later deposits. We find the maple, sloe, hawthorn, cornel, 
elm, birch, alder, hornbeam, hazel, oak, beech, willow, yew, pine, 
and spruce. This is an assemblage that could not well be 
found under conditions differing greatly from those now existing 
in Norfolk. There is an absence of both Arctic and South 
European plants. The variety of trees shows that the climate 
was mild and moist. The occurrence of the maple and horn¬ 
beam show that it can have been little, if at all, colder than 
now. The aquatic plants point to the same conclusion, though 
not so definitely, as the majority of them are widely dispersed. 
Both the fauna and flora, leaving out the large mammals and 
other extinct forms, are curiously similar to those of the “Broad 
District” of Norfolk at the present day; and this, like the rest 
of the evidence, points to a wide alluvial plain with lakes and 
sluggish streams, bounded on the west by a slightly higher 
sandy country covered with fir-forests and distant from any hills. 
A careful examination of the deposits now forming, and of the 
natural history of the neighbouring country, will, more than 
anything else, assist in the study of these Newer Pliocene strata ; 
for, notwithstanding the great changes which have taken place 
since the Forest-bed was formed, conditions almost exactly 
similar to those which held during the deposition of the Upper 
Freshwater Bed, reappear at the present day in the Broad 
District. 
