On light land, the subsoil of which is often full of water, the case is quite different, and the pipes must be laid much deeper to relieve its water-logged condition; but on our stiff clay the subsoil was comparatively dry, and we had to provide only for the discharge of the surface water as quickly as possible, where the solid clay beneath prevented its sinking into the lower layers. In the subsoil of the lias clay there are large numbers of a fossil shell, _Gryphea incurva_, known locally as "devils claws"; they certainly have a demoniac claw-like appearance, and worry the drainers by catching on the blade of the draining tool, and preventing its penetration into the clay. I have heard the suggestion that our highly banked ridges were intended to increase the surface of the land available for the crops, just as it takes more cloth to cover a hump back than a normal one, but of course the rounded ridge does not provide any more _vertical position_ for the crop, and the theory cannot be maintained. Some of these ridges, "lands" as they are called, are so wide and so elevated that it was said that two teams could pass each other in the furrows, on either side of a single "land," so hidden by the high ridge that they could not see one another; and I myself have noticed them on abandoned arable land that has been in grass from time immemorial, so high as nearly to answer the description. Though the blue clay in the Vale of Evesham is so tenacious, it works beautifully after a few sharp frosts, splitting up into laminations that form a splendidly mouldy seed bed, so that frost has been eloquently called "God's plough."