SINO-MONGOLIAN FRONTIER 
masses of detritus, brought down from the moun- 
tains to the iorth, are crossed by the track, and 
they testify to the enormous amount of denu- 
dation that is taking place here. An examination 
of the rocks shows that the mountains to the north 
are composed mainly of granite and gneiss. These 
conditions prevail as far as Yang-kao, the present 
terminus of the line. 
No sedimentary rocks of any kind were noticed 
on this journey, except the massive limestone 
forming a tall range on the south side of the 
Yang Ho valley. Elsewhere on the lower slopes 
a considerable amount of loess was noticed. 
The schists noticed near Tsai-kou-pu probably 
belong to the same formation as the Wu-tai series, 
or are equivalent to it, while the granite and 
gneiss beyond are doubtless equivalent to the 
T’ai-shan Complex. 
PART 7 
THE GEOLOGY OF THE COUNTRY FROM YANG- 
KAO TO K’UEI-HUA-CH’ENG, NORTH SHANSI 
As already stated, Yang-kao is situated on the 
eastern edge of the Ta-t’ung Fu plain. To the 
north lies a great chain of tall rugged mountains. 
These seem to be composed mainly of metamor- 
phic rock, gneiss being the only rock we encoun- 
tered on entering these mountains on our way 
to K’uei-hua-ch’éng. 
273 T 
