, Palestine and
Babylonia-Assyria is unknown in Arabia. Yet the passing notes of
travellers from the time of Carsten Niebuhr show that antiquities are to
be found.

_Prehistoric Remains._--Since prehistoric remains must be studied where
they are found, the difficulty in the way of exploration makes itself
severely felt. That such remains exist seems clear from the casual
remarks of travellers. Thus Palgrave (_Central and Eastern Arabia_, vol.
i. ch. 6) speaks of part of a circle of roughly shaped stones taken from
the adjacent limestone mountains in the Nejd. Eight or nine of these
stones still exist, some of them 15 ft. high. Two of them, 10 to 12 ft.
apart, still bear their horizontal lintel. They are all without
ornament. Palgrave compares them with the remains at Stonehenge and
Karnak. Doughty (_Arabia Deserta_, vol. ii.), travelling in north-west
Arabia, saw stones of granite in a row and "flagstones set edgewise"
(though he does not regard these as religious), also "round heaps,
perhaps barrows," and "dry-built round chambers," which may be ancient
tombs. J.T. Bent (_Southern Arabia_, pp. 24 ff.) explored one of several
mounds in Bahrein. It proved to be a tomb, and the remains in it are
said to be Phoenician.

_Castles and Walls._--In the south of Arabia, where an advanced
civilization existed for centuries before the Christian era, the ruins
of castles and city-walls are still in existence, and have been
mentioned, though not examined carefully, by several travellers. In
Yemen and Hadramut especially these ruins abound, and in some cases
inscriptions seem to be still _in situ_. Great castles are often
mentioned in early Arabian literature. One in the neighbourhood of San'a
was described as one of the wonders of the world by Qazwini (_Athar
ul-Bilad_, p. 33, ed. Wustenfeld, Gottingen, 1847, cf. _Journal of the
German Oriental Society_, vol. 7, pp. 472, 476, and for other castles
vol. 10, pp. 20 ff.). The ruins of the city of Ma'rib, the old Sabaean
capital, have been visited by Arnaud, Halevy and Glaser, but call for
further description, as Arnaud confined himself to a description of the
dike (see below), while Halevy and Glaser were interested chiefly in the
inscriptions.

_Wells and Dikes._--From the earliest times the conservation of water
has been one of the serious cares of the Arabs. All over the country
wells are to be found, and the masonry of some of them is undoubtedly
ancient. Inscriptions are stil