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-Ian-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. Nystrdm, 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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