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

84 GEOLOGICAL RESEARCHES IN
May 31st. Leaving Skunope in the morning, we travelled northward, first through
a thickly wooded, swampy district, with corduroy road, then over a soil of volcanic
ashes, till we finally reached the sea-shore, when turning eastward, we skirted the
northern foot of the volcano, and crossing the outlet of the lake reached the fishing
village of Shkabe.
The northern slope of the mountain was formerly covered with timber reaching
high up its side, and now represented by a forest of dead trunks extending over
thousands of acres. The trees were probably killed by the shower of pumice which
covered the surface to the depth of from six inches to two feet. On a large proportion of the trees the bark is intact, and they show no signs of the action of fire.
A fresh undergrowth was springing up, at the time of our visit, and of this the
climbing plants seem to have been the first to start into life.
In the side of a gulley in the bluff, I observed the following series from younger
to older:1. Layer of pumice, two feet thick.
2. Vegetable mould with roots of grass six inches.
3. Layer of pumice, three to five feet.
4. Thin layers of pumice and sand, apparently an ancient beach.
5. Volcanic conglomerate-breccia.
This section is repeated in all the cuttings observed at the foot of the volcano.
At Shkabe there are several hot springs used for bathing. One of these, rising
on the beach and bubbling strongly, has a temperature of 75~ C.; and in another
rising in a cold stream, but protected by wooden tubbing, I found 70~. The water
of these springs has a slight odor of sulphuretted hydrogen.
June 1st. Soon after leaving Shkabe we passed an outcrop of quartziferous porphyry, showing columnar structure, and remarkable for its richness in double pyramid crystals of pellucid quartz associated with white felspar in a compact gray paste.
The volcanic conglomerate-breccia was the prevailing rock, but in places the bluff
was formed of an apparently younger deposit of sandy clay. The beach was in
many places covered with a layer of magnetic iron sand, from the disintegrated
volcanic rocks, well concentrated by the action of the surf.
From Shkabe eastward many fragments of vein quartz were seen on the beach.
At the mouth of the Kakumi creek we left the sea-shore, and following the wild
valley rode a few miles inland to the mines of Kakumi. Here the hills are formed of
greefish and gray argillaceous rocks in places brecciated, in others metamorphosed
to an euritic rock. These are traversed by dykes of a peculiar white porphyry.
This porphyry has a compact paste, generally very white, sometimes gray or
greenish, yielding fire with difficulty with the steel. In this are scattered grains,
and especially double pyramid crystals, of quartz, which form from a few per cent.
to one-third the volume. In tare instances it contains crystals of a white triclinic
felspar. Mica and hornblende are never present and rarely chlorite. It contains
almost always small cubes of iron pyrites.
In weathering it changes to a white kaolin-like substance often discolored by the
oxidation of the pyrites.
It occurs in dykes, and often shows columnar structure.