Yarkand and Khotan, provinces of Chinese Tartary, which lie beyond the two diagonal chains, are less elevated and more fertile than Tibet; yet it is so cold in winter that the river Yarkiang is frozen for three months. They are watered by five rivers, and contain several large cities; Yarkand, the most considerable of these, is the emporium of commerce between Tibet, Turkistan, China, and Russia. Gold, rubies, silk, and other productions are exported. The Tartar range of the Thian-Shan is very high; the Bogda Oola, or “Holy Mountain,” near Lake Lob, its highest point, is always covered with snow, and it has two active volcanoes, one on each side. This range runs along the 42d parallel of north latitude, forming at its western extremity a mountain-knot with the Beloot Tagh, in the centre of which lies the small table-land of Pamer, 15,600 feet high, called by the natives the “Roof of the World.” Its remarkable elevation was first described by the celebrated Venetian traveller Marco Polo, six centuries ago. The Oxus originates in a glacier of the Pooshtee Khur, a peak of the Beloot Tagh near the plain of Pamer; the lake Sir-i-Kol is here the source of the river of Yarkand; and the Kokan also rises in the same plain, which is intensely cold in winter, and in summer is alive with flocks of sheep and goats. Snow lies deep on the Thian-Shan range in winter, yet little falls on the plains on account of the dryness of the air. There are only two or three showers annually on these mountains, for a very short time, and the drops are so minute as scarcely to wet the ground, yet the streams from them suffice for irrigation. Zungary, or Mongolia, the country between the Thian-Shan and the Altaï, is hardly known, further than that its grassy steppes, intersected by many lakes and offsets from the Altaï, are the pasture-grounds of the wandering Kirghiz.