Subsequent to the cutting down of the continuous aboriginal forests and the making of clearings the country was crudely drained and cultivated. A great deal of this had been already done at the time of the Norman Conquest, for the survey speaks of so many carucates of land, or land under the plough, in each village. And certain parts of the country bear unmistakable signs of this, especially in the Midlands, the land of ridge and furrow. The ridge and furrow was the result of the old-fashioned mode of ploughing, the furrows being the drainage system, the ridge being prepared for the raising of corn.

The boundaries of such fields at right angles to the ridge were termed sillons, and were caused by the necessity of going round the ends, and not up and down alternate furrows as nowadays. These sillons exist to-day, and may be seen to coincide sometimes with present boundaries.

Thus meadow and pasture were once corn land in many cases. Where no such furrows exist the ground may (1) not have been drained and cultivated in early days, or (2) may have been once ridge and furrow and since cultivated recently. In modern cornfields and fields relaid, or "seeds", and fallow land, the ridge and furrow are obliterated. The present system of drainage with pipes is relatively modern, dating usually from the sixteenth or seventeenth century in early cases, but from the eighteenth or nineteenth more generally.

The difference between meadow, pasture, seeds, and fallow should be noted, and lists of plants on each compared. The two last are at first transitional from cornfields with a broken open surface

The effect of cornfields upon the surrounding grassfields should be noticed. It is a neglected feature. The introduction of many cornfield and waste-ground plants into fields is due to the influence of wind blowing seeds, cartage, etc. Where a cornfield is dirty, the surrounding fields will soon be filled with thistles, etc.