244 THE POPULAR SCIENCE MONTHLY. 



root-fibers, and lined with a thin coating of carbonate of lime. The 

 direction of these canals being always from above downward, cleavage 

 in the loess mass, irrespective of size, is invariably vertical, while, from 

 the same cause, water in falling upon a deposit of this material never 

 collects in the form of puddles or lakes on its surface, but sinks at 

 once to the local water-level. 



The loess territory of China begins, at its eastern limit, with the 

 foot-hills of the great alluvial plain — roughly speaking, upon the line 

 drawn from Peking to Kaifung in Honan. From this rises a terrace 

 of from ninety to two hundred and fifty feet in height, consisting en- 

 tirely of loess ; and westward of it, in a nearly north and south line, 

 stretches the Tai-hang Shan, or dividing range between the alluvial 

 land and the hill-districts of Shansi. An almost uninterrupted loess- 

 covered country extends west of this line to Lake Koko-nor and head- 

 waters of the Yellow River. On the north the formation can be traced 

 from the vicinity of Kalgan, along the water-shed of the Mongolian 

 steppes, and into the desert beyond the Ala Shan range. Toward the 

 south its limits are less sharply defined ; though covering all the coun- 

 try of the Wei basin (in Shensi), none is found in Sz'chuen, due south 

 of this valley, but it appears in parts of Honan and Eastern Shantung. 

 Excepting occasional spurs and isolated spots, loess may be considered 

 as ending everywhere on the north side of the Yangtse Valley, and, to 

 convey a general notion, as covering the parallelogram between longi- 

 tudes 99° and 115° east, and latitudes 33° and 41° north. The district 

 within China Proper represents a territory half as large again as that 

 of the German Empire, while outside of the provinces there is reason 

 to believe that loess spreads far to the east and north, possibly in vary- 

 ing thicknesses quite across the desert. Baron von Richthofen ob- 

 served this deposit in Shansi to a height of 7,200 feet above the sea, 

 and supposes that it may occur at higher levels. 



One of the most striking as well as important phenomena of this 

 formation is the perpendicular splitting of its mass — already referred 

 to — into sudden and multitudinous clefts that cut up the country in 

 every direction, and render observation as well as travel often exceed- 

 ingly difficult. The cliffs, caused by erosion, vary from cracks meas- 

 ured by inches to canons half a mile wide and hundreds of feet deep ; 

 they branch out in every direction, ramifying through the country after 

 the manner of tree-roots in the soil — from each root a rootlet, and from 

 these other small fibers — until the system of passages develops into a 

 labyrinth of far-reaching and intermingling lanes. Were the loess 

 throughout of the uniform structure seen in single clefts, such a region 

 would indeed be absolutely impassable, the vertical banks becoming 

 precipices of often more than a thousand feet. The fact, however, that 

 loess exhibits in every locality a terrace formation, renders its surface 

 not only habitable, but highly convenient for agricultural purposes ; 

 it has given rise, moreover, to the theory advanced by Kingsmill and 



