399. RESEARCH IN CHINA. 
to a basin several miles across. The alluvium resembles the Huang-t’u 
formation in texture, color, and structure, but it is horizontally bedded. 
The valley is bounded by bluffs of Huang-t’u, rising to an upland 50 to 
80 feet, 15 to 24 meters, above the present flood-plain, which is continuous 
with that of the high passes south of Ling-shi, and represents the same 
stage of topographic development. 
Considering a north-south section from the basin of T’ai-yiian-fu to 
the plain of P’ing-yang-fu, we note that the surface of the Huang-t’u form- 
ation rises from the basin, where its altitude is about 2,750 feet, 840 meters, 
above sea, to about 4,100 feet, 1,250 meters, between Ling-shi-hién and 
Ho-choéu, and sinks again to about 2,600 feet, 800 meters, at P’ing-yang-fu. 
The buried surface beneath the Huang-t’u conforms nearly to the same 
differences of elevation. It is a surface of mature erosion and was once 
nearly flat. The Fén-ho flows in a canyon, which is deepest where the 
Huang-t’u and the buried topography lie highest; and the Huang-t’u is 
being invaded by many canyons of vigorous youthful growth. These facts 
combine to demonstrate the existence of an arch or upwarp, which trends 
across the valley, probably northeast to southwest. The movement is 
a comparatively recent one, younger than the Huang-t’u formation, and 
the Fén-ho, being antecedent to the upwarp, has cut a canyon in main- 
taining its course. A little further south it was not so successful. 
At P’u-chéu-fu we met Mr. A. R. Bergling, a missionary residing at 
Han-chéng on the Huang-ho, and were told by him that above Han-chéng 
the Huang-ho flows in dangerous rapids through a rocky gorge. It is 
possible that this canyon, like that of the Fén-ho, is cut across the 
northeast-southwest upwarp just described. 
The Fon-ho below P’ing-yang-ju.—The valley of the Fén-ho south % 
P’ing-yang-fu is sunk in the Huang-t’u formation, the bottom of which 
does not appear in sections along the road. There are many deep cuts 
where the road descends to or rises from the gorge of one of the tributaries 
of the Fén-ho, and usually one finds at these points beds of coarse cobbles, 
many of them as large as a man’s head, interstratified with the fine, verti- 
cally cleaved loess. These are obviously deposits of the lateral streams 
from the adjacent high mountains, and they indicate that the Huang-tu 
formation was built up under conditions favorable to at least occasionally 
vigorous water transportation. Ata point about 15 miles, 24 kilometers, 
south of P’ing-yang-fu a bed of marl is interstratified with the loess. The 
marl is about 30 feet, 9 meters, in thickness, of greenish white and buff 
color, and contains minute, very fragile shells which we were unable to 
preserve. The surface of the marl is cut away by a channel of erosion 
which is filled with loess, and beyond this point the exposure was obscure. 
We have here a record of deposition in a fresh-water pond which was 
