152	THE EMPTY QUARTER
side was about 5 miles, and beyond it lay the district of
Sa'afij, in which we remained for the rest of the day and for
the greater part of the next.
It differed from the preceding tract in being an ocean of
sand billows frequently streaked with short ranges of higher
dunes like the breakers of a reef-strewn sea. The dune ranges,
instead of being long and continuous, were long but broken
up into short echeloned lengths; and our course, which entered
the area through a gap between two such runs of dunes, with
the deep bushy valley of Shuqqan al Birkan just beyond
them on our right hand—this valley is said to run south-west
for a considerable distance—ran from gap to gap through no
fewer than 10 of these intermittent ranges until we emerged
on an upland of sandy downs without any dune features to
break its ocean-like regularity. There was little of interest
in the whole tract except that the Abal bush now reappeared
on the bare sandy downs after a long absence from the scene
—somewhat grudgingly it is true, but none the less welcome
to the camels, which had been showing signs of thirst as the
result of many days' restriction to a diet of rather dry Hadh.
In one of the Abal bushes near our track we found an aban-
doned raven's nest, and on the second day we observed two
pairs of ravens apparently contemplating matrimony and
nest-building, while other individuals were seen from time to
time. Small birds were also comparatively numerous—two
kinds of larks and a Wheatear—while our hunters got
several hares.
Our men had certainly been as good as their word, and it
was 5 p.m. before we came up with the baggage party just
as it had selected a site for the evening's camp after twelve
hours of almost unbroken marching. We had covered nearly
30 miles and had thus accomplished our best marching per-
formance since the beginning of the expedition. While the
tents were being erected I walked up to a low rounded sand
barrow to survey the scene with the lad Muhammad who had
taken up his position there to keep an eye on the camels,
which had been turned out to graze on arrival in camp. 'Ali
soon came up to join us and, as we sat there conversing, I
could not help wondering how on earth and why a great