are found with thriving villages and towns.

Jebel Shammar, from which the northern district of Nejd takes its
name, is a double range of mountains some 20 m. apart, rising sharply
out of the desert in bare, granite cliffs. J. Aja, the western and
higher of the two ranges, has a length of about 100 m. from north-east
to south-west, where it merges into the high plateau extending from
and continuous with the Khaibar harra. The highest point, J. Kara,
near its north-eastern extremity, is about 4600 ft. above sea-level,
or 1600 ft. above the town of Hail, which, like most of the larger
villages, lies along the wadi bed at the foot of J. Aja. The town,
which has risen with the fortunes of the Ibn Rashid family to be the
capital of Upper Nejd, is at the mouth of the valley between the twin
ranges, about 2 m. from the foot of J. Aja, and contained at the time
of Nolde's visit in 1893 about 12,000 inhabitants.

The principal tributaries of the W. Rumma converge in lower Kasim, and
at Aneza Doughty says its bed is 3 m. wide from bank to bank. Forty
years before his visit a flood is said to have occurred, which passed
down the river till it was blocked by sand-drifts at Thuwerat, 50 m.
lower down, and for two years a lake stood nearly 100 m. long, crowded
by waterfowl not known before in that desert country. Below this its
course has not been followed by any European traveller, but it may be
inferred from the line of watering-places on the road to Kuwet, that
it runs out to the Persian Gulf in that neighbourhood.

East of Kasim the land rises gradually to the high plateau culminating
in the ranges of Jebel Tuwek and J. Arid. The general direction of
these hills is from north-west to south-east. On the west they rise
somewhat steeply, exposing high cliffs of white limestone, which
perhaps gave Palgrave the impression that the range is of greater
absolute height than is actually the case. J. Tuwek in any case forms
an important geographical feature in eastern Nejd, interrupting by a
transverse barrier 200 m. in length the general north-easterly slope
of the peninusla, and separating the basin of the W. Rumma from that
of the other great river system of central Arabia, the Wadi Dawasir.
The districts of Suder and Wushm lie on its northern side, Arid in the
centre, and Aflaj, Harik and Yemama on its south, in the basin of the
W. Dawasir; the whole of this hilly