176 RESEARCH IN CHINA. 
is approximately 50 miles, 80 kilometers, and its greatest throw is east of 
Ho-ch6u. Going from Foén-chéu-fu, we approached the Ho-shan in the 
vicinity of Kié-hiu-hién, and observed that toward the northeast the 
mountains sink away to relatively low altitudes and gentle slopes, whereas 
toward the south the range grows in height and becomes very abrupt in 
scarp. Its summit was capped with snow, and its relative altitude above 
the valley of the Fén-ho appeared to reach 5,000 feet, 1,500 meters. As 
the float in the streams from the range consisted chiefly of metamorphic 
rocks and the high crest exhibits horizontally stratified beds, we inferred 
that the mass was composed of Pre-Cambrian overlain by the Sinian. The 
valley in which we were traveling was cut in the Shan-si Carboniferous 
series, which was stratigraphically 5,000 feet, 1,500 meters, above the Pre- 
Cambrian, but is topographically 5,000 feet, 1,500 meters, below that 
geological plane. From our route to the base of the range was a distance 
of perhaps Io or 12 miles, 15 or 20 kilometers, a hilly country covered with 
loess such as results from erosion of the soft strata of the Shan-si system. 
There was no evidence of the outcropping of the hard limestones of the 
Sinian, as must have been the case if the relations of the strata in the 
valley and on the mountain crest were established by abrupt folding. The 
stratigraphic relations, indeed, are such as to indicate beyond reasonable 
doubt the presence of a normal fault of 8,000 or 10,000 feet, 2,500 or 3,000 
meters, throw. Physiographic evidence fully corroborates this inference, 
the mountain face having the character of a slightly eroded fault-scarp. 
Opposite the Ho-shan and 30 miles, 48 kilometers, west of it is the 
O-shan (Ngo-shan) fault. It was seen by von Richthofen at San-t’iau-ho. 
He noted the occurrence of coal, which was mined in the valley of the 
Fon at the foot of the O-shan, then traversed a canyon in the limestone 
below the coal-measures, and ascending continually, both in altitude and 
geological position, he reached the village of San-t’iau-ho, where he again 
came upon the coal-bearing rocks.* The attitude of the strata in the 
canyon was nearly horizontal, but the altitude of the coal-measures in 
the mountain is such as to indicate a normal fault of approximately 2,000 
feet, 600 meters, with the downthrow on the eastt. Thus we have between 
the O-shan and the Ho-shan a sunken graben corresponding to the valley 
of the Fon-ho, bounded on the west by the uplifted block of the O-shan and 
on the east by the even more elevated block of the Ho-shan. It does not 
appear that the Ho-shan fault is continuous, either northward or southward, 
and we do not know how far the O-shan fault extends. As that of the 
Ho-shan passes into a warped surface, it is highly probable that that of the 
O-shan likewise does so. 

*China, vol. u, p. 421. flbid., p. 457. 
