Geology.The formation at El Ein is a series of undisturbed sedimentary beds lying horizontally, most of which are sandstones or grits. This overlies unconformably a much older series of gneisses and schists which are exposed in the lower parts of the Wadi El Melh along the foot of the Makakush escarpment a few miles north of El Ein.
The sandstone series is continuous all the way to Debba, and extends over very large tracts of the Sudan.
Mineral deposits.There are no indications of any mineral deposits of value at El Ein in any of the beds exposed.
Old workings.At several points, especially along the sides and just above the stream-bed, there are natural caves in the sandstone. For some little distance a very soft underlying bed has been weathered away undermining a harder upper one, the unsupported portions of which have broken off and fallen, or cracked and bent over, leaving open gashes. The general appearance of all this very much resembles that of an ancient shaft nearly filled up with débris, though a careful examination leaves no doubt that the phenomena are natural.
Ancient buildings.On either side of the gorge about opposite the well is a cluster of ancient houses, while on a hill some way up the gorge and on the south side are some five more.
The houses are all of similar design approximately round, and are well built, without mortar, of unhewn stone laid in courses; the walls are about 2 feet thick, and many of the stones are of great size. The doorways of most of them face down the valley, but a few are on the opposite side. Many have additional rooms built forming segments of circles.
These buildings are more substantial, and differ in other respects from those usually seen round ancient mines in the Sudan. The only implements noted were two crushing stones; these, however, have not been used for crushing quartz (the matrix in which gold usually lies), being of ordinary millstone and not hard enough for that purpose. They were in all probability only the usual stones for crushing grain.
Across the entrance to the gorge is a wall probably originally 6 to 8 feet high, but now in ruins. It is built of unhewn stones, fairly well coursed, without mortar. The sides are vertical. This runs across the flat space at the entrance to the gorge and a little way up the northern slope. The stream bed lies in a creek some 15 feet below the level of the ground on which the wall stands, and there is no evidence of this waterway ever having been blocked.
In view of this as well as of the general construction of the wall, it is impossible that the structure was a dam, but I should imagine it was probably built for defence, and the gorge was used as a place of refuge against marauding bands by a people whose flocks usually grazed in the valley below.
[132]This district is not actually in the Sudan, but owing to its proximity to Halfa, some description of the wells in it is given here.