The Desert of Lop is a section of the Gobi Desert that extends southeastward from the foot of the Kuruk-tagh as far as the present terminal basin of the Tarim, namely Kara-koshun (Przhevalsky's Lop-nor), and is an almost perfectly horizontal expanse, for, while the Baghrash-ko in the north lies at an altitude of 2940 feet, the Kara-koshun, over 200 mi to the south, is only 300 feet lower. The characteristic features of this almost dead-level but slightly undulating region are:

1. broad, unbroken expanses of clay intermingled with sand, the clay (shor) being indurated and saliferous; and often arranged in terraces;
2. hard, level, clay expanses, more or less thickly sprinkled with fine gravel (say), the clay being mostly of a yellow or yellow-grey color;
3. benches, flattened ridges and tabular masses of consolidated clay (jardangs), arranged in distinctly defined laminae, three stories being sometimes superimposed one upon the other, and their vertical faces being abraded, and often undercut, by the wind, while the formations themselves are separated by parallel gullies or wind. Furrows, 6 to 20 feet deep, all sculptured in the direction of the prevailing wind, that is, from northeast to southwest; and
4. the absence of drift-sand and sand dunes, except in the south, towards the outlying foothills of the Astin-tagh.

Perhaps the most striking characteristic, after the jardangs or clay terraces, is the fact that the whole of this region is not only swept bare of sand by the terrific sand storms (burãns) of the spring months, the particles of sand with which the wind is laden acting like a sand-blast, but the actual substantive materials of the desert itself are abraded, filed, eroded and carried bodily away into the network of lakes in which the Tarim loses itself, or are even blown across the lower, constantly shifting watercourses of that river and deposited on or among the gigantic dunes that choke the eastern end of the desert of Taklamakan. Numerous indications, such as salt-stained depressions of a lacustrine appearance, traces of former lacustrine shorelines, more or less parallel and concentric, the presence in places of vast quantities of fresh water mollusc shells (species of Linnaea and Planorbis), the existence of belts of dead poplars, patches of dead tamarisks and extensive beds of withered reeds, all these always on top of the jardangs, never in the wind etched furrows, together with a few scrubby poplars and Eksea gnus, still struggling hard not to die, the presence of ripple marks of aqueous origin on the leeward sides of the clay terraces and in other wind-sheltered situations, all testify to the former existence in this region of more or less extensive freshwater lakes, now of course completely desiccated. During the prevalence of the spring, storms the atmosphere that overhangs the immediate surface of the desert is so heavily charged with dust as to be a veritable pall of desolation. Except for the wild camel which frequents the reed oases on the north edge of the desert, animal life is even less abundant than in the Ghashiun-Gobi, and the same is true as regards the vegetation.