The Min River flows in the eastern borders of the great mountain-plateau mass of central Asia; at Kuan-hsien, it emerges upon the Plain of Chengtu to make its way easily across the Red Basin of Szechuan to the Yangtse at Suifu. The area covered by this report, latitude 30° 55′ to 31° 32′ North, and longitude 103° 18′ to 103° 34′ East, lies along the river, beginning at Kuan-hsien, nearly 40 miles northwest of Chengtu, capital of the province of Szechuan, and extending 40 miles northward to Wei-chou, where the Hsiao Ho enters the Min from the west (Fig. 1).
This is a deep, youthful valley with steep, rocky slopes among mountains, which rise to an altitude of more than 8,000 feet, and peaks, 15 miles west of Wei-chou, which attain more than 11,000 feet. The altitude of the valley floor descends from about 4,400 feet at Wei-chou . . .