摘要
THE HelanMountains sit ina corner of theNingxia Hui Autonom-ous Region of north-western China in a widearc running for 250 kmfrom north to south.Insome places the range is20 to 30 km across;the individual moun-tain peaks are on aver-age 1,400 m above sealevel and the high-est peak Shaguozhou,reaches 3,556 m intothe sky.When the YellowRiver enters
