. A regional geography of the world, with diagrams and entirely new maps . d. A large part of Northern China iscovered by a deposit called loess (see Fig. 90). Theoutflowing winter winds carry with them very fine dustfrom the arid plateau regions over which they havepassed. This dust has accumulated on the margin ofthe plateau, and in the course of time has completelyburied not only the plain, but the mountains and hillswith a mantle of loess often 1,000 ft. thick. The greatdisadvantage of loess is its porous nature, for it is soeasily cut through that rivers and roads often cross it byintrica
. A regional geography of the world, with diagrams and entirely new maps . d. A large part of Northern China iscovered by a deposit called loess (see Fig. 90). Theoutflowing winter winds carry with them very fine dustfrom the arid plateau regions over which they havepassed. This dust has accumulated on the margin ofthe plateau, and in the course of time has completelyburied not only the plain, but the mountains and hillswith a mantle of loess often 1,000 ft. thick. The greatdisadvantage of loess is its porous nature, for it is soeasily cut through that rivers and roads often cross it byintricate passages, on each side of which ar^ very steep,often quite vertical walls. It has, however, the greatadvantage of being fertile, although in this connectionits porous nature is a drawback, and makes irrigation 336 ASIA a necessity in most parts. In colour it is yellow, orbrownish-yellow, hence the names of the Yellow Riverand the Yellow Sea. The chief rivers of Northern China are the Hwang-hoand Pei-ho, or North River. The Hwang-ho rises in CHINA PHYSICAL. FEATURES. Fig. 90.—rhysical map of China. Tibet, and its upper courses arc {q:6. by melting glaciers,which, together with the heavy summer rains of themountainous region across which the upper streamand its tributaries flow, causes disastrous floodswhen the swollen river leaves its narrower mountain « CHINA PROPER 337 bed for the plains of its lower valley. In this part ofits course it does not follow a permanent channel,as, owini; to the deposition of sediment alon^ the bed,the latter is constantly bein^c; raised, so that the riverreally runs on a self-created ridge that is increasingevery year in heic^ht. This, of course, necessitatesthe construction of dykes or embankments in order toconfine the river to its channel, so that there is theever present danger that it may burst the dykesand find a new course. This has happened severaltimes in the past with terrible results, for when thelast serious change took place in 1
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectgeography, bookyear19
