As a gen eral rule, in the early buildings, the crude brick is laid in mud, while the bitumen is used to cement together the burnt bricks.
[Illustration: PLATE 8] These general remarks will receive their best illustration from a detailed description of the principal early edifices which recent researches in Lower Mesopotamia have revealed to us.

These are for the most part temples; but in one or two cases the edifice explored is thought to have been a residence, so that the domestic architecture of the period may be regarded as known to us, at least in some degree.

The temples most carefully examined hitherto are those at Warka, Mugheir, and Abu-Shahrein, the first of which was explored by Mr.Loftus in 1854, the second by Mr.Taylor in the same year, and the third by the same traveller in 1855.

The Warka ruin is called by the natives Bowariyeh, which signifies "reed mats," in allusion to a peculiarity, already noticed, in its construction.

[PLATE VIII., Fig.