248	THE EMPTY QUARTER
benefit of the cool night-hours, while with a few com-
panions I slept on till dawn. I dawdled over my morning
packing. Suddenly Salih, from an eminence commanding
the plain behind us, shouted for my glasses and announced
the presence of suspicious moving things far off. He failed
to substantiate his report but in the desert all alarms must
be taken seriously—true or false,—and we lost no time in
loading up and moving off.
Many weeks earlier 'Ali had confided to me that he knew
of a locality full of shells in these southern parts, and I felt
it was now time to remind him of his promise to lead me
thither. He had indeed not forgotten. He was not alto-
gether sure of the locality but imagined that it was not far
off. He had turned aside once or twice during the previous
day to examine the exposed rock patches we had passed in
case they might prove to be the spot he sought, and here and
there we had found small scattered lots of the little spiral
shells seen at Shanna. We had clearly therefore been
following a river-bed or traversing a delta but now, within
a mile of our camp, we came upon what looked from afar
like another of the numerous patches of exposed rock we
had seen so often. There it is, said 'All. What ? I asked.
The shells I spoke of, he answered ; 'tis many years since I
passed this way and saw them. I was returning from hunting
the Oryx in Qa'amiyat and I paid but little attention to
such things. But when you were so excited at sight of the
shells in the Jiban I remembered. We rode on to the
edge of the exposed patch and I noticed a scatter of
little white spirals. Further on we came upon a few bivalves^1
and I dismounted. We remained there nearly an hour,
collecting the freshwater shells in hundreds and thousands,
while our scouts kept watch on the neighbouring ridges for
fear of foes. Nowhere did I see any trace of flint implements
as at the northern locality, but here was clearly a consider-
able stretch of an old river-bed. A mile further on we found
another similar patch with a more modest deposit of shells.
Thus for something over 20 miles we had found sporadic
evidences of fresh water in ancient times. Nothing but a
^1 Unio terminalia—see Appendix.