The next chain is the Belur-tag, Tartash ling, in Chinese _Tsung ling_, Onion Mountains, or better, Blue Mountains, so called from their distant hue.[4] This range lies in the south-west of Songaria, separating that territory from Badakshan; it commences about lat. 50° N., nearly at right angles with the Tien shan, and extends south, rising to a great height, though little is known of it. It may be considered as the connecting link between the Tien shan and the Kwănlun; or rather, both this and the latter may be considered as proceeding from a mountain knot, detached from the Hindu-kush, in the south-western part of Turkestan called Pushtikhur, the Belur-tag coming from its northern side, while the Kwănlun issues from its eastern side, and extends across the middle of the table-land to Koko-nor, there diverging into two branches. This mountain knot lies between latitudes 36° and 37° N., and longitudes 70° and 74° E. The Himalaya range proceeds from it south-easterly, along the southern frontier of Tibet, till it breaks up near the head-waters of the Yangtsz’, Salween, and other rivers between Tibet, Burmah, and Yunnan, thus nearly completing the inland frontier of the empire. A small spur from the Yun ling, in the west of Yunnan, in the country of the Singphos and borders of Assam, may also be regarded as forming part of the boundary line. The _Chang-peh shan_ lies between the head-waters of the Yaluh and Toumen rivers, along the Corean frontier, forming a spur of the lower range of the Sihota or _Sih-hih-teh_ Mountains, east of the Usuri. ~THE TIEN SHAN AND KWĂNLUN RANGES.~