Geological researches in China, Mongolia, and Japan, during the years 1862-1865.

CHINA, MONGOLIA, AND JAPAN. 25
CHAPTER IV.1
STRUCTURE OF TILE SOUTHERN EDGE OF THE GREAT TABLE
LAND, AND OF NORTHERN SHANSI AND CHIHLI.
Two roads, slightly divergent, lead from Kalgan to Urtai on the'plateau. About
a mile and a half from the town, on the east road, the trachytic porphyry formation appears, under circumstances that would seem to show that much of it is of
pluto-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 about 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 measurement 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 wall
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 hills 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' For this Chapter see Map, P1. No. 2, and Sections, P1. No. 3.
4 April, 1866.