which takes many varieties of tints, lies in veins mostly
striking east-west; and varying in thickness from an inch to
several feet. The sequence is grey granite below, the band of
chalcedony, and above it a curious schistose gneiss-formation.
The latter, composing the greater part of these hills, is striped
dark-brown and yellow; and in places it looks exactly like rotten
wood. The small specimens of chalcedony in my private collection
were examined at Trieste, and one of them contained dendritic
gold, visible to the naked eye. Unfortunately the engineer had
neglected this most important rock, and only a few ounces of it,
instead of as many tons, were brought back for analysis.

A short and easy ascent led to a little counter-slope, the Majra
Mujayrah (Mukayrah), whose whitening sides spoke of quartz. We
rode down towards a granite island where the bed mouths into the
broad Wady Mismah, a feeder of the Wady 'Argah. Here, after some
ten miles, the guide, Na'ji', who thus far had been very misty in
the matter of direction, suddenly halted and, in his showman
style, pointed to the left bank of the watercourse, exclaiming,
"Behold Aba'l-Maru!" (the "Father of Quartz"). It was another
surprise, and our last, this snowy reef with jagged crest, at
least 500 metres long, forming the finest display of an exposed
filon we had as yet seen; but--the first glance told us that it
had been worked.

We gave the rest of the day to studying and blasting the
quartz-wall. It proved to be the normal vein in grey granite,
running south-north and gradually falling towards the
valley-plain. Here a small white outlier disappears below the
surface, rising again in filets upon the further side. The dip is