In one division the bedding of the bricks is strictly horizontal; in the next it is slightly concave, and forms a very flat reversed arch, of which the extrados rests upon the ground.
"Manual Of Egyptian Archaeology And Guide To The Study Of Antiquities In Egypt"
Gaston Camille Charles Maspero
The openings left at the summits of the other courses must have been filled in in some way, and, in fact, the line of voids which ran along the top of the extrados was filled in with brick earth, beaten tight and forming the best of keys.
"A History of Art in Chaldæa & Assyria, v. 1"
Georges Perrot Charles Chipiez
The pavement of the terrace, which consists of a double bed of large bricks, rests upon the extrados of the upper channel.
"A History of Art in Chaldæa & Assyria, v. 1"
Georges Perrot Charles Chipiez