Arkell.1956.Jurassic..

PALESTINE AND TRANSJORDAN 293
the Dead Sea. Here the Nahr es Zerka (Wadi Zerka, Jabbok, or Yabbok)
has cut through the northern edge of a dome and down to the Lower
Trias (Cox, 1932). Above the Lower Trias follow 540 m. of sandstones
before the Cenomanian limestone is reached. Presumed equivalents of
some part of these sandstones yielded a Middle Trias (Muschelkalk)
fauna with Beneckeia cf. buchi (Dunker) not far away to the south, at
Wadi Hesban and Wadi Ayun Musa. In the Zerka area (Wadi Huni)
there are hard grey Triassic limestones with Myophoria, followed by about
200 m. of limestones, sandstones and shales assigned to the Jurassic,
and then by another 200 m. of purple, red and white sandstones without
fossils. The Jurassic beds have yielded many pelecypods and brachiopods
of Bathonian age, including Eudesia cardium (Lamarck), Eligmus rollandi
Douville and Gryphaea costellata Douville, which proclaim them to be a
continuation of the Eligmus-Eudesia beds of Gebel Maghara. Additional
Bathonian forms are Burmirhynchia tumida Buckman (= Rhynchonella
concinna Davidson non Sowerby), Avonothyris jordanensis Muir-Wood
and Heimia furcillensis (Haas). Three other species of brachiopods (a
Heimia, Lobothyris and ? Cymatorhynchia) were taken by Muir-Wood to
indicate the presence of Bajocian strata also, but subsequent collecting
has revealed these species in close association with the Bathonian forms
(Cox, 1925; Muir-Wood, 1925; Blake, 1935, pp. 69-71). In default of
Bajocian ammonites these Eligmus-Eudesia beds should be regarded as
Bathonian. The best correlatives are the 'Bradfordian' beds with
Eudesia cardium and Eligmus polytypus in Normandy.
The outcrops of the Eligmus-Eudesia beds occur near the mouth of
the Yabbok or Zerka valley, and they can be traced for some distance
to the south, along the eastern side of the Jordan valley, in which direction
they are overstepped by Cenomanian limestone (Avnimelech, 1945;
Lees, 1945). This provides further evidence of the Lower Cretaceous
folding and erosion already noticed above.
SYRIA AND THE LEBANON
Offset again to the north, the north-easterly anticlines with Jurassic cores
continue along most of the coastal region of Syria. Between Damascus and
Beirut lie the famous twin anticlines of the Anti-Lebanon and Lebanon,
forming parallel ranges separated by an alluvial valley. The southern end
of the Anti-Lebanon anticline, to the west of Damascus, forms Mount
Hermon, where Lower Oxfordian marls with pyritized small ammonites of
west-European type have long been known through the monograph of
Noetling (1887). The anticline of the Lebanon begins south of Beirut and
runs parallel to the coast past Tripoli, then, after temporary eclipse beneath
basalt, reappears with strike deflected due north as the range of Jebel
Ansariya, in which Jurassic is exposed as far as the port of Ladikiya.
From the western Lebanon came the material studied by Krumbeck in
his monograph on the molluscs and brachiopods of the 'Glandarienkalk'
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