east, through the effects of century-long insolation, wind erosion, great and sudden changes of temperature, chemical action and occasional water erosion. Vast areas towards the north consist of expanses of gently sloping clay, intermingled with gravel. He points out also that the greatest accumulations of sand and other products of wind scouring do not occur in the deepest parts of the depressions but at the outlets of the valleys and glens, and along the foot of the ranges which flank the depressions on the south. Wherever water has been, desert scrub is found, such as tamarisks, Dodartia orientalis, Agriophyllum gobicum, Calligonium sinnex, and Lycium ruthenicum, but all with their roots elevated on little mounds in the same way as the tamarisks grow in the Taklamakan and the desert of Lop. Farther east, towards central Mongolia, the relations, says Futterer, are the same as along the Hami-Su-chow route, except that the ranges have lower and broader crests, and the detached hills are more denuded and more disintegrated. Between the ranges occur broad, flat, cauldron-shaped valleys and basins, almost destitute of life except for a few hares and a few birds, such as the crow and the pheasant, and with scanty vegetation, but no great accumulations of drift-sand. The rocks are severely weathered on the surface, a thick layer of the coarser products of denudation covers the flat parts and climbs a good way up the flanks of the mountain ranges, but all the finer material, sand and clay has been blown away partly southeast into the Ordos, partly into the Chinese provinces of Shen-si and Shan-si, where it is deposited as loess, and partly west, where it chokes all the southern parts of the basin of the Tarim. In these central parts of the Gobi, as indeed in all other parts except the desert of Lop and Ordos, the prevailing winds blow from the west and northwest. These winds are warm in summer, and it is they which in the desert of Hami bring the fierce sandstorms or burans. The wind does blow also from the northeast, but it is then cold and often brings snow, which clears the air of the usual dust haze. In summer, great heat is encountered here on the relatively low (3000–4600 feet), gravelly expanses on the north and on those of the south (4000–5000 feet); but on the higher ground between, which in the Pe-shan