Near the top, the faces are close together, and the waller lays the cover band. This is a course of flat, wide stones laid right across the top of the wall, covering both faces and the hearting between them. It seals the wall from above, so that rain does not run straight down into the middle. It also gives a flat, even bed for the copes, the last stones of all. The stones set aside on the first day, the ones that came off the very top, go here. They were set aside for this.
The cover band is laid level, with each stone sitting tight against its neighbors and bedded firm, so that it does not rock. If the course below is not quite flat, a little hearting or a thin wedge brings it level. The cover stones should be as close to the line of the faces as possible, and in many walls they stand out a little, like the brim of a hat, to throw off the rain.
Then come the copes. These are stones set on edge along the very top of the wall, standing upright or nearly so, packed tightly side by side, like books on a shelf. They are the wall’s last line of defense. Their weight presses down through the cover band into the whole wall, and they make the top harder to dislodge. They also make the wall look finished. A wall without copes looks as though someone left in the middle of building it.
There are different ways of setting copes, and every region has its habits. In some places, they are all of a size and stand straight up, like a row of teeth. In others, a big stone and a small stone alternate, a pattern sometimes called cock and hen. In others, they lean at a slight angle, all in the same direction, each one resting against the next. The hill wall’s copes are of mixed sizes and mostly upright, with the biggest ones set at intervals and smaller ones packed between them.
Copes are set from one end of the gap to the other, and they have to be tight. The waller fits each stone hard against the one beside it, and when a row is nearly done, the last space is filled by a stone chosen carefully to fit it exactly, or by driving a thin wedge between two copes so that the whole row is locked. A good row of copes can be pushed hard from the side and will not move.
When the copes are done, the strings come off and the frames come out of the ground. The waller goes along the wall with a hand, pressing here and there, feeling for any stone that rocks. Usually one or two do. They are fixed. Then the last of the hearting is used to fill any small holes in the faces, and the spare stones, the ones that did not fit anywhere, are stacked neatly at the foot of the wall, where they will be found the next time something needs mending.