The eighth and last district is that of the plain of Jericho, which with the corresponding basin (Ghôr-es-Seisebân) east of Jordan, measures over eight miles north and south, and more than fourteen across, with Jordan about in the middle. The Zor is here about a mile wide, and some 200 feet below the broad plain of the Ghôr.
To sum up shortly the regions thus enumerated. First we have the Huleh marshes; secondly, the basin of the Sea of Galilee; thirdly, the narrow gorge of Kaukab; fourthly, the plain of Beisân; fifthly, the narrow valley below the Bukei'a of Tûbâs; sixthly, the broader region of the Fâr'ah; seventhly, the wide Fusâil Valley; eighthly, the great basin of the Jericho plain; in short, four broad regions connected by two narrow ones, with a marshy lake and valley highest of all, suggestive, as a glance at the map will show, of a former chain of great lakes connected by a river, which have gradually dwindled in area till three small sheets of water alone remain, with the broad dry beds of two others, represented by the Beisân and Jericho basins.
The question thus suggested of the original formation of this great chasm, is not only interesting in itself, but it has a direct bearing on that of the position of the Cities of the Plain.
Various causes of the great depression of the valley have been suggested, among which the action of glaciers has been one of the latest. M. Lartet, the French geologist, was, I believe, the first to point out the clear indications of a great fault or crack, extending all along the valley, which has, in fact, slid down towards the centre of the earth. Special observations were, however, much wanted, and we were able to supply these all along the western side, where apparently they were the most necessary.
To enter into the details of these observations would be impossible in the present work. I propose to sum up the results which seem to me most important, and which I have submitted to geologists for criticism.
The main reason for conjecturing the existence of a fault, is that the formations on the east and west are not the same. On the west we have strata of the age of the English chalk, which dip down very suddenly towards the centre of the valley. On the east we have the Nubian sandstone, with hard limestone above it geologically coeval with our greensand. The section of the present bed of the Dead Sea tells the same story; the deepest part is towards the east, where there is more than ten times the depth of water found near the western shore, and here the mountains rise almost sheer from the lake, while on the west, a succession of steps occurs between the sea and the watershed.