204 J. T. Walker — Exploration of the Sanpo River of Tibet. [Aug. 
could. Crossing to the north bank of the river he went along it eastwards 
for a distance of about 30 miles, nearly down to the point where it is join¬ 
ed from the north-east by a small river, called the Mikchu ; here he had 
to leave the river, and make a considerable detour, up the Mikchu valley, 
and over the Lungla pass on the range which forms the eastern boundary 
of the Lhasa basin, then down the valley in which the Chokorgye monas¬ 
tery is situated half way up and that of Thakpo at its lower end, near the 
town of Gyatsa- Jong on the Sanpo river; here he again struck the river which 
had been wending its way through the mountains for a distance of about 
20 miles while he had been making a detour of over 50 miles. From 
Gyatsa-Jong onwards he kept to the river, until he reached Gyala Sindong, 
beyond which point he could not advance. 
About 30 miles below Gyatsa-Jong he crossed over to the right branch 
of the river near Thakpo Nongjong ; this place is situated near the junc¬ 
tion of a river from the south which is said to pass by the town of Tsari, 
which Lieut. Harman believes is identical with D’Anville’s Chaii. 
Up to Gyatsa-Jong the course of the Sanpo river is fairly in accor¬ 
dance with the course shewn on Pandit Nain Sing’s map of the country 
which he traversed between Lhasa and Assam, via Tawang ; Nain Sing had 
seen the course of the river for a distance of about 30 miles below Chetang, 
and he had been informed that from that point onward it flows in a south¬ 
easterly direction into Assam. We now find that it does flow in a south¬ 
easterly direction, but only for a short distance beyond Gyatsa-Jong, after 
which its course is due east for some 50 miles and then north-east for 
about 80 miles. The river reaches its most northern point near the inter¬ 
section of the meridian of 91° with the parallel of 30°, about 12 miles to 
the north-east of a place which the explorer calls Chamkar, and which 
Lieut. Harman identifies with D’Anville’s Tchamca. 
After attaining its most northern point the river turns due south¬ 
east, reaching Gya-la-Sindong in 15 miles, beyond which place N-m-g was 
not able to follow it. There, however, he saw that it flowed on for a great 
distance, passing through a considerable opening in the mountain ranges 
to the west of a high peak called Jungla, of which the bearing was 130°. 
Deyond this opening the river was said to pass through a country inhabited 
by savages into a land ruled by the British Government. 
Assuming the position of Gya-la-Sindong to have been fairly well 
determined by the explorer, its direct distance from the highest point 
hitherto fixed on the Dihang river, in the course of the survey operations 
in Assam, is only about 100 miles. The height of Gya-la-Sindong was 
found by the explorer to be 8000 feet, showing that the river had fallen 
about 3500 feet in 200 miles of distance from Chetang and leaving a de- 
