Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/98

 by the presence of small veins of sulphur, associated with a white granular gypsum. Pharaoh's Baths. — The hot springs known as Pharaoh's Baths rise partly out of the rock at the foot of the cliff close to the sea, or out of the sand of the beach. The two principal springs are the hottest, with a temperature, according to Figari Bey, of about 160° Fahrenheit, in April 1847, and, according to Russegger, of 157° in October 1838 ; and it probably still remains the same, although I was unable to ascertain this exactly, having only a comparatively short-scale thermometer, which could not be freely exposed to the action of the water without running the risk of bursting it. As it was, the mercury went up to 148 degrees immediately ; and this was the highest point that it was safe to try. The water is clear, with a slight hepatic odour, although no sulphuretted hydrogen could be found by the ordinary tests. It is probably only slightly saline and bitter, like that of all the springs in the lower part of the country near the shore covered by Secondary and Tertiary strata.

Bituminous Limestone. — The white and bituminous limestones cover a considerable tract of country southward and eastward from Hammam Faraoun. The upper flint- conglomerates are seen again, probably as outlying patches, on the summit of a low hill in Wady Atal, where they rise to about 750 or 800 feet above the sea-level — a position that corresponds approximately with the supposed Pliocene beach-line in Figari Bey's map. Lithologically they consist of finely conglomeratic calcareous sandstones, with pectens, and a softer bed full of large oysters, mostly in fragments. These are very similar to the upper brown Tertiary beds overlying the great Nummulitic series at Cairo. The great plain known as the Marcha, north of the mouth of Wady Ferran, is bounded by a continuous escarpment of the white beds, which in places contain sufficient salt to be considered worth working by the Arabs, although no great quantity can be obtained, the mineral occurring in strings and patches in marly beds, not more than an inch or two inches in thickness at most. It is probably from these rocks that the beautifully fibrous and contorted specimens often seen in cabinets, and marked as coming from Arabia, are obtained, as the same structure is very common at the locality in question, which is known as El Laggam, and is near the valley of the same name.

Another good section, illustrating the relative position of the white limestone and the flint-conglomerates, is to be seen in the lower part of Wady Taibe, where there seems to be a considerable local disturbance of the upper beds. The white beds are nearly flat in the valley about two miles up ; but nearer the shore they roll under a series of red conglomerates and grey calcareous sandstones, full of partially rolled fragments of flints of all sizes, with a few pieces of Pecten, dipping seawards at about 25 degrees. A bed of black doleritic lava is interstratified between two of the coarse conglomerates ; and an outlier of the same rock occurs at a higher level further inland, where the beds are flatter. As far, therefore, as can be made out by these instances, the igneous rock is not an intrusive