224 RESEARCH IN CHINA. 
ward along the fault-scarp, it gradually diminished in throw and ultimately 
passed into a warped surface which trends southward. It is thus that 
we approach the valley of the Huang-ho. 
We visited the city of P’u-chéu-fu, which lies in the flood-plain of the 
Huang-ho and had recently suffered from a rise of the river, and thence 
made our way southeastward to the ferry across the Huang-ho at Tung- 
kuan. On leaving P’u-chéu-fu the way continues for several miles over 
the low flood-plain of the Huang-ho, and then rises onto low river terraces 
4 to 10 feet, 3 meters, higher. The village of K’ou-ho was reached in 50 
li, about a half day’s journey. It is at the base of a bluff consisting of 
the Huang-t’u formation, which is here composed almost wholly of loess, 
and which rests on a stratum of very soft sandstone and gravel. The dip 
of these underlying strata is locally 12° to 18° to the west, but lessens 
westward until they finally lie flat. The sequence of the strata observed 
from below upward is sandstone, 15 feet, 4.5 meters, upon the eroded 
surface of which is deposited gravel, 6 to 8 feet, 2.5 meters, followed by 
the Huang-t’u formation, 80 feet, 24 meters, to the top of the bluff. Two 
slight normal faults, probably of very small throw, were observed, the 
strike being north and south and the hade steep toward the west. This 
deposit underlying the Huang-t’u formation appears to be an ancient 
river deposit, which must be assigned to an epoch antedating the accumu- 
lation of the Huang-t’u formation in this particular locality. 
A mile west of K’ou-ho our road led through a very narrow gulch 
up to the surface of the Huang-t’u, about 125 feet, 35 meters, above the 
flood-plain of the Huang-ho. This surface is nearly level and has the 
characteristics of a river flood-plain. On the north it is bounded bya zone 
of hills 100 to 150 feet, 30 to 45 meters, higher, which are greatly dissected 
by well-developed gullies. They either consist entirely of the Huang-t’u 
formation or are covered by it. Back of these hills the slope merges into 
alluvial cones and thence into the foothills of the Féng-huang-shan, which 
rise very gently toward the main range (see Fig. 54). The south slope 
of the mountains is thus in strong contrast with the northwestern. The 
latter is precipitous, the former so gentle that one might almost drive a 
carriage up it. One is a normal fault-scarp, the other a tilted topographic 
surface upon which the accelerated streams have not yet accomplished 
any great amount of erosion. 
From the terrace about 135 feet, 40 meters, above the Huang-ho, 
the descent to the river at Tung-kuan is through a sharp steep gulch in 
the loess. The width of the river’s channel at this point, from bluff to 
bluff, is probably between 2,000 and 3,000 feet, 600 and goo meters. 
Extensive mud flats occupy much of the space at the low stage of water 
