leaving exposed the Plutonic rocks, which now form the crest of the great 

 divide between the F^n 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 F6n 

 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, igio). 



The foregoing remarks refer chiefly to those parts of the mountains west 

 of the F6n Ho which lie outside the path of the present Expedition. I 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 Fen Ho cuts through this formation. The height of the 

 limestone cliffs here must be between 300 and 400 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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