QUATERNARY. 197 
The great plain of eastern China, in latitude 40° north, reaches 
into the mountains in the form of a bay, which is 45 miles across at 
its mouth on the southeastern side and extends 30 miles in a northerly 
direction. It lies across the trend of ridges whose opposed sections form 
parts of otherwise continuous ranges, and the level plain is related to the 
mountains about it as an arm of the sea is to lofty shores. This embay- 
ment is appropriately called the Bay of Peking, as the city of that name is 
situated at the mouth of it. 
Two large rivers, the Pei and Hun, together with several smaller ones, 
enter this bay, flowing in general southerly courses. The Pei and the Hun 
have wide-branching head-waters in the mountains. They are subject 
to floods and carry large volumes of sediment. The Hun is said to be 
the larger stream in the rainy season, though it is considered a tributary 
of the Pei. The relative altitudes of the two show that the Hun has 
deposited more sediment than the Pei. 
Peking is situated between the Pei and the Hun, 14 miles west of 
the former and 10 miles east of the latter, the American Legation site 
being taken as a reference point in the city. It is about 12 miles south- 
east of the base of the Western Hills and from 25 to 40 miles distant from 
mountains on the north, northeast, and east. The open plain slopes 
very gently away to the south and southeast. 
The altitude of the Belgian Railway station west of the Ch’ién- 
m6n is 45 meters, or 147 feet, above sea, according to official records 
furnished by M. Jadot, director of the railway. The American Legation 
site, near by, is a trifle higher, its altitude being about 155 feet above sea. 
By the same authority the altitude of the railway bridge over the Hun 
river at Lu-k’ou-kiau is stated at 66 meters, or 215 feet. The height of 
the bridge above the river being about 15 feet at low water, the river is 
in round numbers 50 feet above Peking. 
The available figures for the relative elevations of Peking and the 
Pei river are based on readings of two aneroid barometers, one being 
read at Peking, the other being carried to Tung-ché6u and read there as 
well as at Peking. It appears that Peking is 60 feet, more or less, above 
the plain of the Pei at Tung-chéu. 
The altitudes of mountains immediately surrounding the Bay of 
Peking, as determined by the Intelligence Branch of the British North 
China Command, range from 1,500 to 4,200 feet above sea. The mountains 
are very sharply sculptured, are exceeding steep, and descend without 
notable foothills to the plain. Their rocky slopes continue beneath the 
alluvium of the plain. Spurs extend out into the plain like promontories 
into a sea, and isolated hills rise like islands through the deposits in which 
their bases are buried. 
