Physical geography. By Mary Somerville ...

82 PHYSICAL GEOGRAPHY. CHAP. VI,
The lower valley of the Indus throughout partakes of the character
of the Punjab; it is fertile only where it is within reach of water;
much of it is delta, which is occupied by rice-grounds; the rest is
pasture, or sterile salt marshes.
South of the Punjab, and between the fertile plains of Hindostan
and the left bank of the Indus, lies the great Indian desert, which
is about 400 miles broad, and becomes more and more arid as it
approaches the river. It consists of a hard clay, covered with shifting sand, driven into high waves by the wind, with some parts that
are verdant after the rains. In the province of Cutch, south of the
desert, a space of 7000 square miles, known as the Run of Cutch,
is alternately a sandy desert and an inland sea. In April the waves
of the sea are driven over it by the prevailing winds, leaving only
a few grassy eminences, the resort of wild asses. The desert of
Mekran, an equally barren tract, extends along the Gulf of Oman
from the mouths of the Indus to the Persian Gulf: in some places,
however, it produces the Indian palm, and the aromatic shrubs of
Arabia Felix. It was the line followed by Alexander the Great returning with his army from India.
The scathed shores of the Arabian Gulf, where not a blade of
grass freshens the arid sands, and the uncultivated valleys of the
Euphrates and Tigris, separate Asia from Arabia and Africa, the
most desert regions in the old world.
The peninsula of Arabia, divided into two parts by the Tropic
of Cancer, is about four times the size of France. No rivers, and
few streams or springs nourish the thirsty land, whose barren sands
are scorched by a fierce sun. The central part is a table-land of
moderate height, which however is said to have an elevation of 8000
feet in the province of Haudramaut. To the south of the tropic
it is an almost interminable ocean of drifting sand, wafted in clouds
by the gale, and dreaded even by the wandering Bedouin. At wide
intervals, long narrow depressions cheer the eye with brushwood and
verdure. More to the north, mountains and hills cross the peninsula from S.E. to N.W., enclosing cultivated and fine pastoral valleys adorned by groves of the date-palm and aromatic shrubs. Desolation once more resumes its domain where the table-land sinks into
the Syrian desert, and throughout the rest of its circumference it
descends in terraces or parallel ranges of mountains and hills to a
flat sandy coast from 30 to 100 miles wide, which surrounds the
greater part of the peninsula, from the mouth of the Euphrates to
the Isthmus of Suez. The hills come close to the beach in the province of Oman, which is traversed by chains, and broken into piles
of arid mountains not more than 3500 feet high, with the exception
of the Jebel Okkdar, which:is 6000 feet above the sea, and is cleft
by temporary streams and fertile valleys. Here the ground is cultivated and covered with verdure, and still farther south there is a