The mountains that bound the Asphaltic Lake on the east and west are as remarkable for their native grandeur as for their historic associations. Those on the east are portions of the Moab and Edom ranges; the one descending from the north and the other ascending from the south, are separated midway the sea by the sublime chasm of El-Môjib. The former is composed of sandstone, with sections of limestone, and with dikes and seams of trap rock, over which are scattered quantities of post-tertiary lava, pumice-stone, and volcanic slag; the latter is in part sandstone with strata of limestone; while at the extreme south there is a post-tertiary deposit of carbonate of lime, with sandstone disintegrated, and with a mixture of sulphur and gypsum. Rising from 2000 to 3000 feet high, the eastern range is rugged and barren, and, from a peculiarity in the atmosphere, is perpetually veiled in a purple haze. The sides are broken by twelve ravines desolate and wild. Less than ten miles from the northeast angle of the sea, at the mouth of Wady Zŭrka Ma’in, are the warm springs of Callirrhoe, sending forth, between grand and lofty sandstone cliffs, a copious stream, in whose thermal waters Herod the Great sought, in vain, relief from his loathsome disease. It is twelve feet wide, ten inches deep, and has a temperature of 95° Fahrenheit. Its banks are lined with canes and tamarisks, and the pebbles are tinged with the sulphurous waters. The chasm is 112 feet wide, and from eighty to 150 high, through which the torrent sweeps to the sea at the rate of six knots an hour. High up the ravine is a pretty cascade, with a perpendicular fall of six feet, and below it the foaming waters rush over a succession of rapids. In this sublime glen purple flowers bloom, and ravens and butterflies wing their tireless flight. On the very brow of the northern cliff stood the famous fortress of Machaerus, where John the Baptist was beheaded.[306] Two miles to the south, on the borders of a little streamlet, is a grove of thirty date-palm-trees; three miles farther is a bright cascade, whose sparkling waters leap into the sea from the very mountain summit; and five miles beyond is the ancient river Arnon, on whose banks Balak met Balaam,[307] and which was the southern boundary-line of the Amorites, whose dominion ran northward to the Jabbok. This tract of land Moses conquered from Sihon,[308] and for it the Ammonites fought with Jephthah[309] while it was possessed by the tribes of Reuben and Gad.[310] The Arnon is a tributary to the sea, eighty-two feet wide, four deep, and one hundred wide at its mouth. The vast fissure through which it falls is ninety-seven feet wide, and varies from 100 to 400 feet high. The cliffs are red, yellow, and brown sandstone, and, worn by the winds and rains, resemble Egyptian architecture. In graceful curves the ravine winds inward, and in its profound depths are huge boulders, which have fallen from the summit above.