GEOLOGIC HISTORY OF CHINA BLACK WELDER. 391 



fifteen times in the last 3,000 years. In these incessant shiftings the 

 river has strewn all over an enormous area, 500 miles from north to 

 south by 300 miles from east to west, layer after layer of fine yellow 

 loam or silt ; the very name " Yellow River," which is a translation 

 of the Chinese " Hwang-ho," suggests the close resemblance to our 

 own mud-laden Missouri. Almost every square foot of this vast 

 alluvial fan is, of course, underlain by a deep and fertile soil, and is 

 intensively cultivated by the industrious Chinese inhabitants. One 

 sees no large fields of grain, such as those on our Dakota prairies, 

 but, instead, thousands of small truck gardens belonging to the 

 inhabitants of the hundreds of little mud-walled villages with which 

 the plain is dotted. The ever-present town walls have doubtless been 

 built, because the inhabitants have no natural refuges, as their moun- 

 tain cousins have, and their very accessibility has made them in the 

 past the frequent prey of Mongol and Tartar invaders or of rebels 

 and rioters from within their own country. 



Since the water supply of the plain is not lavish but little rice is 

 grown there. The dry-land grains and such vegetables as cabbages 

 and potatoes are the staple crops. The small gardens are sparingly 

 irrigated, however, in times of drought, by water taken from the 

 canals or wells, with the help of various types of crude pumps oper- 

 ated by men or by donkeys (pi. 2. fig. 5; pi. 5, fig. 5). 



In this densel}^ populated alluvial plain there is practically no 

 pasturage and no woodland. From the very nature of the plain it 

 could not yield coal, which is always associated with the solid rocks. 

 To bring fuel, as we do, from distant parts of the country is impos- 

 sibly expensive for the Chinese, without an adequate railroad system, 

 and that is still a thing of the future. When the harvest has been 

 gathered in the autumn the village children are therefore sent out 

 to gather up every scrap of straw or stubble that can be used either 

 for fodder or for fuel. The fields thus left perfectly bare in the 

 dry winter season afford an unlimited supply of fine dust to every 

 wind that blows. This is doubtless the explanation of the disagree- 

 able winter dust storms with which everv foreigner who has lived 

 in northern China is only too familiar. 



Although carts and wheelbarrows are much used on the Hwang 

 Plain, their traffic is chiefly local. That may be due in part to the 

 fact that the numerous wide and shifty rivers are difficult to bridge, 

 while ferrying is relatively expensive. Another, and perhaps more 

 important, reason is that the rivers, and particularly their old, aban- 

 doned courses, afford natural waterways which are available nearly 

 everywhere. By taking advantage of these or by deepening them, 

 and in some places by actually digging canals through the soft 

 material of the plain, the Chinese have put together the wonderful 

 system of interlaced canals for which they have been renowned since 



