886 
Wilson.—Plant Distribution in the 
of the Thanet Sand. As would be expected, an acid reaction is constantly 
given by the soils in woodland areas. The proportion of mineral plant 
food also is generally lower than in soils of the Thanet Sand. 
The areas of woodland occurring on the formation are not extensive 
in the districts under consideration. In the majority of cases the Woolwich 
and Reading beds form a relatively narrow zone in the Lower Eocene deposits 
bounded on one side by the Thanet Sand and on the other by the Oldhaven 
beds. Occasionally, however, in the smaller outliers in which the Oldhaven 
beds are not represented, the Woolwich and Reading areas are more 
extensive. It has already been pointed out that there is in many cases 
a gradual transition from the Thanet Sand to the Woolwich and Reading 
deposits. 
(a) Woods on the sands and gravels of the Woolwich and Reading 
series. The following woods of this type have been investigated :— 
In the Faversham district: portions of Bysing and Perry Woods. 
In the Swanley district : portions of Jordan’s, Farningham, and 
Rowhill Woods. 
The woods in many respects are similar to those occurring on the 
Thanet Sand. In the coppices, Chestnut is frequently the most abundant 
species, but it is mixed with a considerable proportion of Oak and Beech. 
The occurrence of Beech on a soil containing so small a proportion of 
calcium carbonate is of interest. Pyrus Aria , Ehrh., is frequently found ; 
this tree, although widespread on the Chalk, is not confined to calcareous 
deposits, but is of general occurrence on light soils. In some of the woods 
Pinus sylvestris , L., has been extensively planted, and here the coppice 
is more open and felling does not take place at regular intervals. In 
consequence the sharp distinction between the light and shade vegetation 
already described in the case of coppice on the Chalk, Clay with Flints, and 
Thanet Sand cannot in these cases be maintained. 
The flora of the Woolwich and Reading formation is distinguished 
by the abundance of Pteris aquilina , L. This plant, which occurs spar¬ 
ingly or not at all on the Thanet Sand, is dominant in all situations 
where the illumination is sufficient to allow for its development. Adoxa 
Moschaiellina , L., and Ranunculus Ficaria , L., are absent, while Primula 
acaulis , L., Anemone nemorosa , L., and Endymion nutans , Dum., occur very 
sparingly. 
The light flora generally resembles that already described on the more 
stony soils of the Thanet Sand, but is more xerophytic in character. 
Cardmis palustris , L., is rarely or never found, while there is a larger pro¬ 
portion of Teucrium Scorodonia , L., and Solidago Virgaurea , L., Calluna 
Erica , DC., and Air a flexuosa , L., are usually present. Poly trichum 
juniper inum, Willd., occurs in addition to the Mosses already noted on the 
Thanet Sand. 
