Loi Too-ey is said to be the highest mountain in the country, and forms part of the spinal range which divides the waters of the Meh Kong, or Cambodia river, from those of the Salween. Just to the north of this mountain a freak of nature has occurred, such as is frequent in Western China and Indo-China,—the upper sources of the Meh Hang, which naturally belong to the drainage of the Meh Ping, have percolated through a fault in the great range of hills, and now find their way by an underground passage into the Salween. Before this passage was made, the head-plains of the Meh Hang formed the bottom of a great lake which was, and is still partially, drained by the Hua Sai, a branch of the Meh Soom into the Meh Ping. Two ancient cities, Muang Hâng and Muang Teung, and several villages, are situated in the old lake-basin which forms part of the British Shan States; it is solely occupied by Burmese Shans, and was included in the Burmese Shan States under the name of Muang Hâng. The upper parts of the Meh Ping and Meh Teng valleys are likewise occupied and owned by Burmese Shans, although claimed by the Zimmé Shans as part of their State; and I was told that the possession of the basins of the Meh Pai and Meh Fang is also a moot question and a subject of quarrel between our subjects and those of the Siamese. These questions will have to be fixed by the Boundary Commission appointed for demarcating our frontier with Siam. Leaving the Meh Teng, we crossed a low plateau partially crowned with teak-trees to the Meh Ping at a point where the river is contracted to 70 feet in breadth. Continuing through the teak-forest, we skirted the Meh Ping, the hills on either side gradually drawing in, until at 28½ miles the defile commenced, the slopes of the spurs fringing both sides of the river. Shortly afterwards we halted for the night, near a stream of petrifying water, which had turned the gravel in the river-bed opposite its mouth into a bank of conglomerate, and forced the river to take a rectangular bend, cutting into the hill on the opposite bank.