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

CHINA, MONGOLIA, AND JAPAN. 33
extend northward to the high plateau. The southern side of the valley is formed
by a lower ridge, beyond which higher mountains are seen, and over these the distant snow-capped1 peaks, or rather domes, of the range south of the Sankang Ho.
Leaving the valley of the Yang Ho near Tienching, we cross over the terracecapped ridge before mentioned, into the valley of Hwaingan khien). To the north
of the road in crossing, and north of the whole valley of Hwaingan, the hills are
seen to consist of alternating strata of a bright red rock and of a harder rock, in
anticlinal and synclinal folds. The fragments brought by streams from the hill
forming the western part of the southern side of the valley, are gneiss and hornblende schist.
Following the Hwaingan creek to the northeast, the road approaches, near where
it emerges into the valley of the Yang Ho, a fine section in the strata of the northern
hills. Resting on gneiss are strata of highly metamorphosed rocks, the continuation
of those we saw in the hills between Siuenhwa (fu) and Kalgan, and which for the
present may be called the Hwaingan beds. The valley of Hwaingan trends N. E.
by E., and this seems to be about the strike of the strata. In the exit into the
valley of the Yang Ho, the Hwaingan creek flows through a gorge formed by the
erosion, parallel to its axis, of an anticlinal ridge of the Hwaingan beds.
From this point our road crosses the valley of the Yang Ho, and brings us again
to Kalgan.
KALGAN TO SIWAN AND SINPAUNGAN.
Leaving Kalgan the road runs in a northeasterly direction through a deep gorge,
with vertical walls, in the Kalgan trachytic porphyry, and its pluto-neptunian
deposits, as far as Ulanhada. At this village it leaves the valley of the main stream,
and turning into a tributary valley, winds with this through the mountains, following
an easterly course to the Roman mission of Siwan. For eight or ten miles we see
only the rocks of the Kalgan porphyry, but before reaching the village of Siyin'sz,
these are followed by the crystalline metamorphic schists, which in turn are succeeded, before we reach Siwan, by syenitic granite. This last is eruptive, dykes
of it traversing the metamorphic strata, and the main body often containing fragments of the schists. This rock forms the mountains around and beyond Siwan.
From Kalgan to this point, and beyond, the terrace deposit occupies the sides of
the mountains, and at Siwan its terraces form the sides of the valley to the height
of from 200 to 300 feet above the creek, and its vertical cliffs show it to be a fine,
compact loam. In it the Chinese excavate their dwellings in suites of apartments
having doors, windows, and partition walls, all cut in the loam. The walls are
simply plastered over to prevent the dust from falling, and in this condition they
last as long, if not longer, than the ordinary houses built of sunburnt clay.2 In the
i 26th April, 1864.
2 These excavations are common wherever the terrace deposit occurs in Northern China.
5 May, 1866.