The roofs are formed by placing slabs so that each course overlaps the lower one until the opening becomes about 5 ft.
The XIIth Dynasty.This age overlaps the previous in its style.
As in the south of England, the lower beds of the Cretaceous are of estuarine origin and the Upper Cretaceous overlaps the Lower, lying in the valley of the Ruhr directly upon the Palaeozoic rocks.
At other times they are at different levels, and are applied over each other, so as to be imbricated, as in lilac, and in the outer scales of sycamore; and occasionally the margin of one leaf overlaps that of another, while it in its turn is overlapped by a third, so as to be twisted, spiral or contortive.
In glazing, the greater the surface of glass, and the less space occupied by rafters and astragals as well as overlaps, the greater the admission of light.