The Conglomerates, formed of well-worn and rounded pebbles, occur at 
an altitude of about 500 feet. The Pyrites, a grey and friable variety, occurs 
at an altitude of between 300 and 4oo feet. The sulphur is extracted by the 
natives, who roast the pyrites in perforated clay vessels, the residue being a 
soft, earthy substance the colour of yellow ochre. When roasted again, this 
turns into a bright red powder, largely used in the manutacture of paint for 
houses and furniture. In places, where the second roasting is carried on, 
the whole of the surrounding ground, for a considerable distance, becomes 
stained a bright red. Many such patches mark the slopes of these mountains, 
and might at first sight be mistaken for outcrops of Red Hematite. 
The coal from this district is also very sulphurous, and unpleasant to use 
in open grates, being very smoky and giving a large percentage of ash. In 
places, where the seams were exposed to the air, we often noticed an 
efflorescence of pure sulphur. 
There is also a considerable amount of iron-ore in these mountains; and 
some of the streams in the range are strongly alkaline: a fact especially 
noticeable when they are frozen. 
After crossing this ridge, we descended first through loess and then 
through shale to the bed of the Fén Ho at Ku-chao. Here, a little way up 
the ravines, which join the river, iron-smelting is carried on; brown iron- 
ore being easily mined. Iron, coal and clay occur together in these spots ; 
otherwise, there would be no smelting done. The price of pig-iron is too low 
to allow of any one of these materials being transported for use from a 
distance. Baron von Richthofen has described the native method of smelting 
so well that any further remarks would be superfluous. 
The formations, from Ku-chao westward for a distance of twenty miles, 
are entirely of Sandstone, Shale and Huang-t'u. As already stated, the strata 
of these sedimentary rocks were found to be horizontal, and free from foldings 
and faults. 
At Ts’a-k’ou, about forty-five miles west of T’ai-yiian Fu, Sinian Lime- 
stone again makes its appearance, and a little further on the Pre-Cambrian 
rocks, which form the Chiao-ch’éng Shan district, commence. We first 
travelled up a long valley leading westward, the sides of which were composed 
of precipitous limestone peaks. As we ascended the pass at the head of this 
valley, we crossed a dyke of Pegmatite exposed in the cutting of the bridle- 
path, the rest of the slopes being composed of Mica Schists. Onthe western 
slope of the pass, masses of white Felspar with large pieces of embedded 
Muscovite were noticed. Large stones of both fine and coarse-grained Granite, 
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