The best of all subsoils is a dry bed of clay overlying sandstone.
Tenacious soils and subsoils, with a small supply of water, require beds as narrow as 30 ft.
The subsoils of some of the other districts (Cotes and St Emilion) contain much stone in the shape of flint and quartz.
The soft limestone underlying this region is covered, in the uplands, with grey, sandy soils, which have a subsoil of loam; in the lowlands the surface soils are loams, the subsoils clays.
It might indeed have been thought that thorough drainage would be unnecessary, but it must be noted that porous subsoils or efficient drains do not act merely by carrying away stagnant water which would otherwise cool the earth, incrust the surface, and retard plant growth.