148 Brenchley.—The Weeds of Arable Land . III. 
B. Loams. 
By far the greater part of the soils investigated in Norfolk are loams, 
locally known as ‘ mixed soils ’, varying in texture from light sandy land to 
that of a very heavy nature. A local distinction is drawn between a ‘ sand ’ 
and a ‘ light mixed soil * and between a ‘ heavy mixed soil ’ and a ‘ clay \ but 
this distinction does not hold good when the weed flora is considered. 
Between the lightest and the heaviest loams there is an intermediate range 
of loams with which certain weeds are more particularly associated. It seems 
as though some species of plants do not care for extremes of any kind, but 
flourish best in the less distinctive habitats. Among such species are : 
Anthemis Cotula 
Beilis perennis 
Brassica alba 
Chrysanthemum leucanthemum 
Euphorbia Peplus 
Lolium perenne 
Lychnis dioica 
Papaver Argemone 
generally associated with loams. 
Achillea Millefolium 
Galeopsis Tetrahit 
Legousia hybrida 
Scabiosa arvensis 
Sisymbrium officinale 
Veronica agrestis 
> also on sand and sandy loam. 
Centaurea nigra — also on chalk. 
Poa trivialis — perhaps characteristic of the heavier soils. 
Equisetum arvense 
Lychnis Githago 
Potentilla Anserina 
Prunella vulgaris 
more usual on loams, but also 
associated with other types 
of soil. 
C. Sand and Sandy Loams. 
These soils are met with all over the county, and in most cases repre- 
sent the sand and gravel deposits, in others the lightest types of Boulder 
Clay. In some places the sands are deficient in calcium carbonate ; in others, 
where the chalk rock comes near the surface, they are decidedly calcareous, 
containing chalk stones, as is well seen at Hargham and East Snettisham. 
In the north-west of the county the Lower Greensand crops out in the form 
of ‘ carstone ’, which yields a peculiar type of sandy soil deficient in chalk, 
