CHINA, MONGOLIA, AND JAPAN. 25 



CHAPTER IV.^ 



STRtrCTURE OP THE SOUTHERN EDGE OP THE GREAT TABLE 

 LAND, AND OP NORTHERN SHANSI AND CHI II LI. 



Two roads, slightly divergent, lead from Kalgaii to Urtai on the plateau. About 

 a mile and a half from the town, on the east road, the trachytic porphyry forma- 

 tion appears, under circumstances that would seem to show that much of it is of 

 pluJjO-neptunian origin. 



This formation extends several miles further north and northeast till it is limited 

 by the metamorphic schists of the range. On the west road the same formation 

 exists till near Tutinza, on the northern side of the range, and furnishes slabs of 

 tufa and blocks of porphyry for building purposes. 



The country crossed by the road between the Barrier range and the edge of the 

 plateau is a depression, here abput nine miles broad. On either side of the road 

 are flat-topped hills 80 to 100 feet high, of gravel made up in great part of rolled 

 fragments of quartziferous porphyry. This gravel, which I take to be of the same 

 age as the lake loam and terrace deposits, also forms the low hills traversed by the 

 eastern road, where it covers a brown-coal basin probably of tertiary origin, of which, 

 unfortunately, I was able to see only specimens of the coal. 



About half way between Tutinza and Hanoor the road begins to rise to the 

 plateau, and leaving China proper, with the edge of the table-land, we reach the 

 steppes of Tartary. 



The height of the edge is here 5,400 feet above the sea, according to the measure- 

 ment of Fuss and v. Bunge, and probably not less than from 3,000 to 3,500 feet 

 above Changkiakau, and the edge itself forms a precipitous wall to the south, while 

 the plateau slopes off gently to the north. 



From a tower of the Great Wall, which crowns a hill near Hanoor, we have, 

 spread out before us, a grand panorama of the surrounding country. The natural waU 

 formed by the abrupt termination of the table-land stretches away from the tower 

 far off to the west and northeast, bounding the valley south of it as a precipitous 

 coast bounds the sea. Between us and the Barrier range, the depression, occupied 

 by low hiUs of the eroded gravels, lies like a neutral belt between two regions of the 

 earth in almost every respect widely different each from the other. To the south 

 only barren and rugged mountains meet the eye, and beyond these to the Southern 

 Ocean, the mountainous character is redeemed only by the fertile valleys of a few 



* Por this Chapter see Map, PI. No. 2, aud Sections, PI. No. 3. 



4 April, 1866. 



