(f.) Age of the Volcanic Eruptions.—It is very clear that the first eruptions, producing the great basaltic sheets of Moab and Arabia, occurred after the principal features of the country had been developed. The depression of the Jordan-Arabah valley, the elevation of the eastern side of this valley along the great fault line, and the channels of the principal tributary streams, such as those of the Yarmûk and Zerka Maïn, all these had been eroded out before they were invaded by the molten streams of lava. Now, as these physical features were developed and sculptured out during the Miocene period, as I have elsewhere shown to be the case,[11] we may with great probability refer the volcanic eruptions to the geological epoch following—namely, the Pliocene. How far downwards towards the historic period the eruptions continued is not so certain. Dr. Daubeny, quoting several passages from the Old Testament prophets,[12] says it might be inferred that volcanoes were in activity even so late as to admit of their being included within the limits of authentic history. The poetic language and imagery used in these passages by the prophets certainly lends a probability to this view, but nothing more. On the other hand, these regions have suffered through many centuries from the secondary effects of seismic action and subterranean forces, and earthquake shocks have laid in ruins the great temples and palaces of Palmyra, Baalbec, and other cities of antiquity. The same uncertainty regarding the time at which volcanic action died out, with reference to the appearance of man on the scene, hangs over the region of Arabia and Syria, as we have seen to be the case in reference to the extinct volcanoes of Auvergne, the Eifel, and the Lower Rhine. In all these cases the commencement and close of eruptive action appear to have been very much about the same period—namely, the Miocene period on the one hand, and that at which man entered upon the scene on the other; but in the case of Syria and Western Palestine, the close of the volcanic period may have been somewhat more than 2000 B.C.
[1] Lake Phiala, near the Lake of Huleh, is also situated to the west of the Jordan valley. Its origin, according to Tristram, is volcanic.
[2] Schumacher, "The Jaulân," Quarterly Statement of the Palestine Exploration Fund, 1886 and 1888; and Across the Jordan, London, 1886.
[3] Lartet, Voyage d'Exploration de la mer Morte (Géologie), Paris, 1880.
[4] Tristram, Land of Moab, London, 1873; and Land of Israel, 1866.
[5] Niebuhr, Beschreibung von Arabien, 1773.
[6] C. M. Doughty, Arabia Deserta, 2 vols., 1888. A generalised account of this volcanic region by the author will be found in the "Memoir on the Physical Geology of Arabia Petræa, and Palestine," Palestine Exploration Fund, 1887.
[7] Schumacher, loc. cit., p. 248.
[8] Land of Israel, p. 461.
[9] "Geology of Arabia Petræa, and Palestine," Memoirs of the Palestine Exploration Fund, p. 95.