28 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
height. The rest of the surface is low or undulating, generally about twelve 
feet above sea-level but in many places very little above the sea. 
The outline of the peninsula as given on the chart is only approximately 
correct ; it is broken up by many intricate “ Khors” or inlets of the sea, of 
which “ Khor Rawaya”’ is but one. 
A section of the Northern plateau is given by a cliff about 60 feet high 
which borders a fault, now full of sea-water, known as Khor Atof. The 
drawing given (PI. 4) shows its structure, which is typical of the whole of 
this peninsula. Above is a mass about six feet thick of recent corals (A), all 
in the position of growth. The large numbers of shells which accompany 
these are still more easily identified as being of living species. 
Next is a thicker stratum apparently of consolidated coral-mud (B & C), 
containing two characteristic fossils, nullipore nodules and a clypeastrid 
echinoderm. The latter occurs in large numbers and is easily recognized as 
a species still living in Khor Atéf. 
This is all the reef formation present *. Below it is a bed of gypsum (D) 
of varying thicknesses up to 12 feet, this resting on a finely laminated and 
very soft sandstone (EH), generally yellow in colour but here often dark green 
or red. 
The coral formations are in horizontal strata, and are unconformable to the 
strata on which they rest, which are considerably folded and contorted. 
In the lower parts of the peninsula, the coral stratum is thicker, e. g. at 
Haysoit Island up to 15 feet are exposed, the coral-mud and other strata not 
appearing above the sea-level. The hill in the south (Jebel Abu Shagara) 
is similar, forming a great cliff bounding the fault in which lie two inlets of 
the sea, “ Khor Rawaya” opening northwards, and Khor Abu Shagara which 
runs in from the open sea, 7. e. from the south. The view eastwards from 
the summit is striking, the peninsula here consisting of a series of parallel 
ridges and troughs, the result of smaller faults, some of which-contain sea- 
water inlets. These, like all the Khors above named, run approximately north 
and south. Jebel Abu Shagara is itself cleft by a great north and south 
gash in its southern part, which may be taken as one of the coast inlets 
elevated above the sea for our examination. It shows the same structure as 
the cliff on the east side, viz., a shallow cap of coral underlaid by gypsum 
and sandstone as in the north, but here the gypsum band is narrow and may 
be absent, the sandstone in any case forming the great bulk of the hill. This 
rock forms also the bulk of the islands of Makawa and Mayiti, which are 
about 500 and 300 feet high respectively. I have not climbed Makawa, but 
Mayiti is coral-capped. The east side of all these hills is precipitous, the 
west sloping. 
* T have found no elevated reefs thicker than 15 feet on the Sudan coast. This agrees 
with the accounts given of those of poth shores of the Gulf of Suez and the Sinai Peninsula. 
