SINO-MONGOLIAN FRONTIER 
sedimentary rocks, doubtless belonging to the 
Shansi formation. First we came to some very 
massive conglomerate. This is composed of large 
cobbles and small boulders, held together by a very 
hard matrix containing sand and small pebbles. 
The strata of this conglomerate, which are very 
marked, and often over ten feet in thickness, dip 
to the north-west at angles varying from 45° to 
80°. 
They are interstratified with small, pinched-out 
seams of coal and soft shale. In places the con- 
glomerate is much contorted. 
At Wu-lan-pan, a village six miles north-west 
from Pi-ch’ien-ch’i, the conglomerate gives place 
to pink and yellow sandstone, with a much gentler 
dip (about 20° N.W.). 
Beyond Wu-lan-pan the conglomerate again 
appeared, underlying a dark brown shale, this 
time at a dip equal to that of the sandstone. 
After this we came to high mountains, composed 
chiefly of metamorphic rocks, through which great 
masses of granite protrude, forming a system of 
high peaks. No volcanic rock was noticed in this 
district. 
My friend Mr. Nystrém, already mentioned 
in Part I of this chapter, tells me that, when in 
the mountains north of Sa-la-ch’i (or Saratsi), one 
day’s journey west of this point, he encountered 
outcrops of sedimentary rocks exactly similar 
to those described above, and, like me, he arrived 
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