The general geological formation of Palestine is simple. The basis of the country—the great body of its hills and plains—is Jura limestone ; the same which extends over Lebanon, the desert of Arabia, and the plateau southwards to the mountains of Sinai. Russegger says it may be classed with the Upper Jura formation, the oolite, and the Jura dolomite.' The rock is not uniform in character, composition, or colour. Most of it is compact, regularly stratified, of a dark cream or gray colour, and abounding in fossils. As a general rule it be comes softer towards the south. At Bethel are `large masses of blue limestone with shells,' and on the sides of Gerizim is nummulitic limestone ; in some parts the rocks had been in a liquid state, for one kind had overflowed and encased the other' (Poole, in journal of R. G. S., xxvi. 56). Around Jerusalem dolomite prevails. The ancient build ings of the city appear to have been chiefly con structed of it. It is veined with red and white like marble, compact, partially crystallized, and takes a high polish. Traces of an upper cretaceous for mation of a more recent period are visible over the whole mountains. In many places the action of the atmosphere and the washing of winter rains have stripped it from the firmer strata. It was filled with masses and nodules of flint ; and these are now strewn over the surface where the son chalk, in which they were originally embedded, has entirely disappeared. Between Nabulus and Sa maria the ground is covered with flints (Poole, 57) ; they abound in the wilderness of Judaea. On the road from Bethany to Jericho, Poole says, white nodules with black flint in the centre were thickly strewed about' (id.) In some places less exposed the upper crust remains ; and thin layers of sand stone, soft and friable, alternate occasionally with the chalk (id.) Towards the borders of the Dead Sea some important changes are observed in the strata. Of the mountain of Neby Mfisa, Poole says, The soil smelt very strong of sulphur, and I got specimens of limestone of an oolite structure, also of a seam of bituminous and calcareous lime stone, with pictens about six incises thick' (58) On the northern shore of the Dead Sea he got a specimen of bituminous stone. In the mountain along the south-west coast, the chalk showed in several places overlaid by limestone,' probably owing to the tilting of the strata, or some other volcanic -agency. In eastern Palestine the lime stone is found in Hermon, and throughout Gilead and Moab ; but at Keralc it gives place to the ruddy sandstone strata which constitute the moun tains of Edom, and which also appear beneath the limestone along the eastern shore of the Dead Sea. This eastern region has not been visited by any practical geologist, and the notices of it are brief and unsatisfactory.
This field of limestone, which thus extends over all Palestine, has been interrupted and broken in several places, and in a very remarkable manner, by volcanic agency ; an agency, however, which operated at a very remote geological period. In eastern Palestine lava ejected from the earth in a state of fusion has flowed over the limestone, cover ing the whole area of the kingdom of Bashan. The centre of eruption appears to have been in Jebel Hauran, at the now extinct craters Tell Abu Tumeis and Kuleib. From these two craters lava streams flowed westward to the Lejah ; and the Lejah itself is filled with smaller craters. The little conical and cup-shaped tells, which stud the surface of Hauran, were all at one time active vol canoes. The basalt thus emitted from numerous openings spread over the whole region, forming the lofty peaks of Jebel Haman, and sweeping across the plain to the Jordan. Neither the breadth nor the exact limits of this lava-field are yet known. On the north-west it runs up the sides of Jebel el Hish ; on the north it is bounded by the river Awaj (Pharpar), which separates it from the lime stone in the plain of Damascus. On the south it runs to the banks of the Yarmuk, and in places across the ravine to northern Gilead. The Lejah is geologically the most remarkable province in Palestine. The hard black rock covers the entire surface to a depth of from thirty to one hundred feet—now stretching out in broad wavy reaches, divided by fissures of great depth—now thrown up in vast heaps of jagged fragments- -now partially crystallized, and extending in long ridges like the Giant's Causeway. The rock is very hard, gives a metallic sound when struck, and is filled with air bubbles. Spherical boulders of the same material are strewn over portions of the western declivity of the plain (Porter's Damascus, ii. 241, seq.; Wetz stein, Relrebericht iiber Haurdn, pp. 27, seq.; Wil son, Lands of Ike Bible, ii. 318, seq. ; Burckhardt,
Travels, pp. seq.) On the west side of the Jordan, opposite Bashan, are two other lava-fields. The northern has its centre about three miles north-west of Safed, near the village of Jish. Dr. Robinson thus describes it :—` We soon came out upon a high open plain ; and the volcanic stones increased as we advanced, until they took the place of every other ; and, besides covering the surface of the ground, seemed also to compose the solid formation of the tract. In the midst of this plain we came upon heaps of black stones and lava, surrounding what had evi dently once been the crater of a volcano. It is an oval basin, sunk in the plain . .. between three and four hundred feet in length, and about one hundred and twenty feet in breadth. The depth is perhaps forty feet. The sides are shelving, but steep and ragged, obviously composed of lava ; of which our friend Mr. Hebard had been able to dis tinguish three different kinds or ages. . . . All around it are the traces of its former action, exhi bited in the strata of lava and the vast masses of volcanic stones. It may not improbably have been the central point, or Ableiter, of the earthquake of 1837' (B. R., ii. 444). From this place the lava streams and boulders radiate to a considerable distance. The high terrace which projects from the eastern side of this ridge to the Jordan below Merom is chiefly basalt ; but it seems to be con nected with the Hauran field, as it is of a hard, firm texture, while that of Jish is soft and porous.
Another centre of volcanic action in former ages is on the high plain south-west of Tiberias, called Ard el-Hamma. The whole plain is a lava-field and the double peak of Kuran Hattin, on its north side, is basalt, and so also is the ridge which bounds the Sea of Galilee on the south. The rock is similar to that of Bashan. The thickness of the bed may be seen in the cliffs on the mountain-side behind the warm baths of Tiberias. The base of these cliffs is limestone, while the whole superin cumbent mass is black or dark-gray basalt. This field extends northward to the plain of Gennesaret, westward to Sefarieh, and southward to Esdraelon. The soil covering it is thick black mould like that of Bashan. It appears that the greater portion of the substratum of Esdraelon is basalt, hidden beneath the soil (Wilson, ii. 304). But Jebel ed Duhy (Little Hermon), and all the hills south of the plain, are limestone ; and volcanic rock is not again seen in western Palestine (Anderson, Geolo gical Reconnaissance in Lynch's Official Report, PP. 124, seq.) On the east of the Dead Sea basalt appears in boulders dotting the plateau between the river Amon and Kerak ; and Burckhardt says it is more porous than any specimens he had found farther northward (Travels, p. 375, cf. ; Anderson, P. But the grand geological feature of Palestine is the central valley or chasm. Hugh Miller has said—' the natural boundaries of the geographer are rarely described by straight lines. Whenever these occur, the geologist may look for something remarkable' (Old Red Sandstone, p. 120). No better proof of this could be found than the Jordan valley. It runs in a straight line through the centre of Palestine. Its formation was probably simultaneous with those volcanic agencies that created the eastern and western lava-fields. It is a tremendous rent or fissure a hundred and fifty miles in length, rending asunder the whole lime stone strata from top to bottom. Its extreme depth from the lips of the fissure to the bed of the Dead Sea is above 4000 feet, no less than 2624 of which is beneath the level of the ocean. * Such a cleft in the earth's crust is without a parallel. It is singular that, though the rent was doubtless effected by a volcanic convulsion, and though volcanic rock covers such a large area on both sides of the northern part of the valley, there are no traces of it in the southern and deepest part, except at one or two points to be afterwards noticed. The sides of the valley, and the rock in its bed, so far as visible, are limestone, ranged occasionally in horizontal strata, but usually upheaved and tossed into wild confu sion. Along the eastern shore of the Dead Sea, the limestone strata give place to sandstone (SEA). The sides of the valley, and the general conforma tion of the adjoining ridges, would seem to indi cate that the limestone crust had been heaved up by some tremendous volcanic agency running from south due north, and causing that huge rent which forms the basin of the Dead Sea and the Jordan valley. May it not be that this agency was the lava-stream which at length found an exit at the craters of Tiberias, Jish, and Hauran ? This subject is well worthy the attention of future geo logists.