392 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, 



Europeans first visited them. The thousands of junks which ply 

 these waterways maintain a volume of inland commerce, which is 

 inferior only to that of the great railroad countries, such as the 

 United States. The relative freedom of communication in this great 

 plain of the Yellow River has helped to bring about a greater homo- 

 geneity in the people than in any other equally large part of China. 

 Here we find a single dialect in use over the entire region, whereas 

 in some parts of southern China the natives of even adjacent valleys 

 speak languages almost unintelligible to each other. The other com- 

 mon effects of isolation, such as the lack of acquaintance with the 

 customs of outside peoples, the hatred of foreigners, the peculiar 

 local usages, and many other things, are less prominent here than in 

 other parts of the empire. Excepting the coastal cities, there is no 

 safer part of China for foreigners to travel through. 



West and northwest of the Yellow River Plain lie the more rugged 

 plateaus and mountains of northwest China, with their subarid 

 climate presaging the approach to the deserts of Mongolia. Over 

 much of this region the ancient limestones and sandstones are still 

 horizontal or are gently folded, with occasional dislocations along 

 faults. On account of the comparatively recent uplift and differ- 

 ential warping which this part of China has suffered, the streams 

 have been greatly accelerated in their work, so that they have hol- 

 lowed out canyons in the raised portions and have filled in the de- 

 pressed basins with sand and silt. This is the region celebrated 

 among geologists on account of the loess, or yellow earth, which lines 

 the basins and mantles the hillsides everywhere. It is believed that 

 this is very largely a deposit of wind-blown dust, although it has been 

 worked over considerably by the streams from time to time. No 

 doubt Baron von Richthofen, the distinguished German explorer, 

 was near the truth when he concluded more than 40 years ago, that 

 the " yellow earth " was the dust of the central Asian deserts carried 

 into China by the northwest winds. The presence of the loess deter- 

 mines, in large measure, the mode of living adopted by the inhabi- 

 tants. Because of its fertility and moisture-conserving properties, 

 it is well adapted to dry farming, and there is little water for irriga- 

 tion. The Chinese are not content with using the level bottom lands, 

 but successfully cultivate the hillsides wherever a deposit of the loess 

 remains. In order to prevent the soil from washing off from these 

 steep slopes, they build a series of stone walls, thus forming soil 

 reservoirs or terraces. In this way nearly all of the soil is utilized. 



In such a country rivers are not numerous and those which exist 

 have many rapids and shoals. Boats are therefore but little used in 

 northwest China. For both passenger and freight traffic, pack ani- 

 mals or rude vehicles are the chief reliance. For passengers there 

 are also the palanquin or sedan chair and the mule litter. Where the 



