hundred miles, I cannot but think that the mines of precious
ores, mentioned by the mediaval Arabian geographers,[EN#38] lay
and lie in offsets from the flanks either of the maritime or the
inland chain; that is, either in the Tihamah, the coast lowlands,
or in the El-Nejd, the highland plateau of the interior.

What complicates the apparently simple ground is the long line of
volcanic action which, forming the eastern frontier of the
plutonic granites and of the modern grits, may put forth veins
even to the shores of the 'Akabah Gulf and the Red Sea.[EN#39]
The length, known to me by inquiry, would be about three degrees
between north lat. 28 and 25 , the latter being the parallel of
El-Medinah; others make them extend to near Yambu', in north lat.
24 5'. They may stretch far to the north, and connect, as has
been suggested, with the Syrian centres of eruption, discovered
by the Palestine Exploration. I have already explained[EN#40] how
and why we were unable to visit "the Harrah" lying east of the
Hisma; but we repeatedly saw its outlines, and determined that
the lay is from north-west to south-east. Further south, as will
be noticed at El-Haura, the vertebrae curve seawards or to the
south-west; and seem to mingle with the main range, the mountains
of the Tihamat-Jahaniyyah ("of the Juhaynah"). Thus the formation
assumes an importance which has never yet been attributed to it;
and the five several "Harrahs," reported to me by the Bedawin,
must be studied in connection with the mineralogical deposits of
the chains in contact with them. It must not be forgotten that a
fragment of porous basalt, picked up by the first Expedition near
Makna, yielded a small button of gold.[EN#41]

Dreadfully rolled the Sinnar, as she ran close in-shore before