Genesis 11:3

Let us make brick, for in that low and fat soil they had no quarries of stones. The heathen writers agree that Babylon's walls were made of brick. The slime was a kind of clay called bitumen, which, as Pliny testifieth, is liquid and glutinous, and fit to be used in brick buildings, as Strabo, Dion, and others note. And that Babylon was built with this, as is here said, we have the joint and express testimony of Berosus, Ctesias, Dion, Curtius, and many others.