'THE GEOLOGY AND MINERAL RESOURCES OF DHUFAR PROVINCE, MUSCAT AND OMAN' [‎33v] (56/96)

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these metamorphic rocks. There is thus a possibility that the
rocks with gypsum veins and bituminous matter in the wadi A seasonal or intermittent watercourse, or the valley in which it flows. Ghaiz
may be the equivalent of these (3) beds, and that both may be the
same as the Micaceous sandstones (4) of the Jabal Samhan scarp
base. It is possible also that these beds (3), as above considered,
might be the equivalent of Littles Hisn Baqirdan (Corallian) in
Makalla (and grouped with (4) ). With regard to (5), which appear
to be quite conformably laid on (4), there is the possibility that
these strata are the equivalents of Little’s Asfal el’Ain (Neocomian)
of Makalla and/or Lees’ Cenomanian marls at Sireir (opposite
Hamar an Nafur island) on the mainland of the gulf of Masira.
73. The most complex question has been the geological age of
( 6 ) the Samhan Hills limestone (see paragraphs 65, 66 , 67, 68 and
69). I found no fossils in the basal beds of these limestones, but I
noted that they sloped south-westward to be in situ along the sea-
cliff mentioned by H. J. Carter (near the island rock of Guena).
If the fossils collected by Mr. Carter on the summit of Jabal Samhan
are considered as Cretaceous, there is nothing more to say than that
they are the only limestones of this kind in southern or south-eastern
Arabia. They do not correspond with the Cretaceous (sandstones)
of Makalla, nor are they the petrological equivalents of those beds
referred to by Dr. Lees at Sireir (on the gulf of Masira). Lees shows
the Samhan Hills limestone to be as old as Cenomanian (page 606
of his paper) and the Sireir beds to be Campanian (though he puts
both under the same colour on his geological map). The matter is
of considerable interest, and until a detailed investigation is carried
out I propose to regard the Jabal Samhan limestones as lower
Lutetian and possibly of Laki, but probably of lower Kirthar age,
with the equivalent of the Ranikot (Landenian to Montian) missing.
Qara Mountain Limestones
74. So far as the rocks from Takah to Risut are concerned
there is great uncertainty since the plains of Dhufar are, along the
coast, covered by the Miliolitic limestone and around the edge of the
plains, along the foothills, the strata appear to be considerably higher
in the sequence than the basal limestone of the Jabal Samhan ( 6 ).
We have no fossils from Risut and the limestones there (7) are, for
the present, correlated with ( 8 ) the Qarn Shaiba limestones, which
from good fossil evidence are fixed as middle Eocene or Kirthar
(middle Lutetian). It is in these strata that ‘chalky limestone’ is
noticeable almost everywhere, and, in the Hanun wadi A seasonal or intermittent watercourse, or the valley in which it flows. the beds
are, in certain layers, saline and the ‘dead’ white beds, near the
top of the section, are pure dolomite. The next younger subdivision
of these extensive limestones of Dhufar are those of the cliffs above
Obet and the wadi A seasonal or intermittent watercourse, or the valley in which it flows. at Heelah. The fossils from the outcrops at
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