leaving exposed the Plutonic rocks, which now form the crest of the great 
divide between the Fén and Yellow Rivers. 
There is plenty of good coal in the district, as well as a certain amount of 
silver ore. The former is mined, but the mining of the latter is prohibited by the 
local officials, who fear the imposition of heavy taxes by the central Government. 
In the Ning-wu district I discovered a series of small lakes situated at an 
altitude of about 7,000 feet above sea-level along the summits of the shale 
ridges of the Shansi formation. They occur in hollows formed by scarps on 
the one side, and dip-slopes on the other: their existence bearing testimony 
to the impervious nature of the shale. The accompanying sketch shows one 
of these lakes, and other physiographical features of the district. The lakes 
are very deep and contain clear, sweet water. Their overflows join the Fén 
Ho, in spite of the fact that they are much closer to the Huai Ho, which 
flows northward, and ultimately joins one of the rivers traversing Chihli. 
(An account of the discovery of these lakes was published in ‘ Travel and 
Exploration,” October, 1910). 
The foregoing remarks refer chiefly to those parts of the mountains west 
of the Fén Ho which lie outside the path of the present Expedition. JI will 
now take in more detail the rocks and formations noticed along our own line 
of march. On entering the mountains west of T’ai-yiian Fu, the first rock 
encountered was the dark limestone (Cambro-Ordovician) dipping slightly to 
the west. This is deeply cut through by water-courses which enter the plain 
from the west. At Lan-ts’un, a village about fifteen miles north-west of 
T’ai-yiian Fu, the Fén Ho cuts through this formation. The height of the 
limestone cliffs here must be between 300 and 4oo feet. A similar formation 
occurs again about three miles north-east of the same village. Here a narrow 
winding gorge cuts deeply through the limestone for a distance of about 
fifteen miles. The limestone, in places, exhibits a pale creamy colour. This 
outcrop appears to form the eastern edge of a great, but shallow synclinal 
fold. The western outcrop appears along the eastern side of the great divide 
of igneous rock, already mentioned. ‘ 
At a level of about 300 feet above the plain, the Limestone formation 
gives place to the Sandstone and Shale formations typical of Shansi. These 
continue the crest of the range to an altitude of 2,500 feet above the level of 
the plain. The shale deposits in this small range are horizontal and free from 
faults, and are inter-stratified with beds of Pyrites, Conglomerates, and thick 
seams of coal. The colours of these shales vary considerably, being blue-grey, 
dark madder, yellow ochre, greenish yellow, or green. 
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