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

CHINA, MONGOLIA, AND JAPAN. 101
The relative ages of the metamorphic and intrusive rocks of this region appear
to be as follows, reading from younger to older:1. Greenstone of Nichinbe; dyke in syenitic granite.
2. Syenitic granite.
3. Aphanitic rock.
4. Metamorphic conglomerate and granulite of Oouta.
5. Amygdaloid.
September 1st. Continuing the journey by boat we reached Kudo-the syenitic
granite forming high hills along the sea as far as Ouenkoto, near Kudo.
At Kudo other metamorphic strata were observed, consisting of black and rosecolored quartz-schist, clay slate in thin beds, and a dark brown, micro-crystalline
rock, apparently felspar and hornblende. These strata are folded and refolded,
and the stratification being well preserved, they presented the finest example of
plication I had ever seen. The general trend of the folding seemed to be about E.,
but there was too much irregularity in this respect to make sure of the direction;
further south the trend appeared more regularly N. W. and the dip N. E.
The beds are traversed by a dyke of a porphyritic rock containing crystals of
green and greenish-white triclinic felspar and of hornblende, in a grayish purple
base.
A cold spring of chalybeate and carbonated water rises on the beach from the
quartzite.
September 2d. Riding along the sea-shore, a few miles, we reached the penal
establishment of Ousubetz, at the mouth of a creek of the same name.
Ascending this stream, which is a wild mountain torrent contained, near the sea,
between cliffs of the volcanic conglomerate, we came upon an amygdaloidal rock,
and beyond this a chloritic granite containing, besides quartz and chlorite, white
orthoclase and a light green triclinic felspar. In this granite there is a broad belt,
apparently a dyke, of a claystone-porphyry, a yellowish rock with a rough, earthy
base free from visible quartz, and from which the crystals of felspar have disappeared, leaving only their cavities. From this porphyry issue several springs,
which showed in different instances temperatures of 55~, 58~, and 58?~ C.
These springs have formed deposits, of carbonate of lime and brown oxide of iron,
which are more or less cavernous, and are the abode of a great number of snakes,
which, attracted by the perpetual warmth, and being respected by the natives as the
deities of the place, live unharmed. The cast-off skins of these reptiles flutter, like
streamers, from every hole and neighboring bush.
Beyond the chloritic granite we found again the amygdaloid which, under various
forms, extended as far inland as our excursion continued, about one mile beyond
the chloritic granite.
In one of the side ravines a bluish-white, highly silicious rock, with conchoidal
fracture and impregnated with minute cubes of iron pyrites, was observed in contact with the amygdaloidal rock.
This amygdaloid is very variable in character, in places brecciated, in others
massive-the base being generally dark reddish-brown, and containing nodules of
calcite and a green, soft clayey mineral, with here and there one of quartz. Frag