In edifices of crude brick, the reeds were no doubt of great service, and have enabled some buildings of the kind to endure to the present day.

They are very strikingly conspicuous where they occur, since they stripe the whole building with continuous horizontal lines, having at a distance somewhat the effect of the courses of dark marble in an Italian structure of the Byzantine period.
Another characteristic of the edifices in which crude brick is thus largely employed, is the addition externally of solid and massive buttresses of the burnt material.

These buttresses have sometimes a very considerable projection; they are broad, but not high, extending less than half way up the walls against which they are placed.
Two kinds of cement are used in the early structures.

One is a coarse clay or mud, which is sometimes mixed with chopped straw; the other is bitumen.

This last is of an excellent quality, and the bricks which it unites adhere often so firmly together that they can with difficulty be separated.