link between China and Tibet, for ferrying across the upper reaches of the Ta Tu is impracticable most of the year.
After passing the bridge we kept up a narrow trail that clung to the face of the cliff, often cut out of the granite rock. There were no villages, but we passed through one or two hamlets set in a small alluvial fan such as is often seen in Western Tibet, only there the fan ended with a steep precipice two or three hundred feet above the river, while here it sloped gently down to the water's edge.
Occasionally we saw across the Ta Tu on the left bank a village unmistakably Tibetan: no trees; grey, flat-roofed, fortress-like houses, often reached only by a ladder; with few signs of life to be seen even with a glass, there was a forbidding aspect to these places in marked contrast to the bustle of a Chinese village.
We were now skirting the lower slopes of the Ta Shueh Shan, or "Great Snow Mountains," the outposts of the Tibetan plateau, but we were too hemmed in to catch a glimpse of the higher ranges, save once, when a break in the mountain wall afforded a brief, magnificent view of the snowy peaks towering more than fifteen thousand feet above our heads. Then another turn in the road shut us in again between grey cliff and grey river and grey sky. Toward the end of the day a sharp bend to the left took us away from the Ta Tu into the wild gorge through