Strabo Geography 16.3.3

[3] “Having coasted the shore of Arabia to the distance of 2400 stadia, there lies, in a deep gulf, a city of the name of Gerrha, ¹ belonging to Chaldaean exiles from Babylon, who inhabit the district in which salt is found, and who have houses constructed of salt: as scales of salt separated by the burning heat of the sun are continually falling off, the houses are sprinkled with water, and the walls are thus kept firm together. The city is distant 200 stadia from the sea. The merchants of Gerrha generally carry the Arabian merchandise and aromatics by land; but Aristobulus says, on the contrary, that they frequently travel into Babylonia on rafts, and thence sail up the Euphrates to Thapsacus ² with their cargoes, but afterwards carry them by land to all parts of the country.