PRESENT ACTIVITY OF EROSIVE AGENCIES 129 



away on either side. It is owing to this position of the river that peri- 

 odical floods so often devastate the interior, and that the mouth of the 

 Hoangho is subject to such variation. The river now empties into the 

 gulf of Pechili, about 150 miles south of Tientsin, but not long ago it 

 wandered over the southern plain and joined the Yangtsekiang 150 miles 

 above Shanghai, 400 miles south of its present outlet. On the other 

 hand, at the present time, during extreme floods, portions of the water 

 turn off to the north, near Kaifun, and, after a course of 350 miles, join 

 the Peiho at Tientsin. Indeed, this most fertile portion of the Chinese 

 Empire is a broad delta of modified loess deposited by the Hoangho, its 

 base extending from Tientsin to Shanghai, a distance of 600 miles, and 

 its apex having a breadth of about 300 miles. 



A general impression of the rapidity with which the denudation of the 

 loess is proceeding may be formed by noticing the extent of dense muddy 

 water which borders the whole Chinese shore of the Yellow sea. When 

 40 miles out from Shanghai, the traveler encounters a sharply cut line, 

 which can be distinctly seen for a long distance in either direction, sepa- 

 rating the clear water of the ocean from the turbid, opaque, silt-laden 

 water brought down by the great Chinese rivers. It is thus evident that 

 deposition of loess is now taking place with great rapidity all along the 

 Chinese side of the Yellow sea. 



This is further shown by the extensive shoals and sand banks which 

 extend from Shanghai nearly to the Shantung peninsula. They mark 

 an extension of the combined delta of the Hoangho and of the Yangtse- 

 kiang, as the former has from time to time turned its flood in that direc- 

 tion; but the historical record of the growth of land on the gulf of 

 Pechili is still more convincing of the activity of this transporting in- 

 fluence. Pao-to, on the Peiho river, was near the shore 200 B. C. It is 

 now 40 miles inland. As .late as 500 A. D. the sea was 18 miles nearer 

 Tientsin than it is at the present time, while the increasing difficulty ex- 

 perienced by ships in approaching the harbor of Taku, at the mouth of 

 the Peiho, is confirmatory evidence of the rapidity of this sedimentation. 

 The records show that all along the shore of the gulf of Pechili the land 

 for the last 2,000 years has been gaining on the sea at the rate of about 

 100 feet per annum. These facts need to be borne in mind when con- 

 sidering the date of the period of the accumulation of the loess over the 

 interior region penetrated by these Chinese rivers. 



Loess on the Border of the Plain of Peking 



Peking is situated near the northeastern extremity of that broad belt 

 of modified loess stretching out on either side from the Hoangho which 



