PETROLOGY: IDDINGS AND MORLEY 
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of quartz with considerable normative hypersthene. The normative 
feldspar is strongly calcic. 
Recent lava from the north rim of the central crater of the volcano 
Aso, is pyroxene-andesite, anal. 2, with nearly the same chemical com- 
position as the basalt from Fuji yama, and with slightly more normative 
quartz, but no modal olivine, so far as observed. The normative feld- 
spar is less calcic and there is less of the femic components. The 
chemical resemblance between the two rocks is well shown by the sym- 
bols and magma tic names. 
The lava of Niokiba crater, Nazu volcano, which was erupted in 1881, 
anal. 3, is typical bandaite, that is, it is a pyroxene-andesite with labo- 
radorite feldspars and a notable amount of normative quartz, some of 
which appears as quartz phenocrysts. The next six rocks, anals. 4 to 
9, are pyroxene-andesites, which are transitional bandaites, since the 
normative feldspars are andesine-laboradorite. The lavas occur at 
widely scattered volcanoes, Zao San, Asama yama and Azuma yama on 
the main island, Hondo; Ohachi, and Shimasaki, a quarry near Kuma- 
moto, on Kyushu; and Komagatake, on Hokkaido. 
The lava erupted from Tarumai, Hokkaido, in 1909, anal. 10, is chemi- 
cally similar to the preceding, but the feldspars are slightly less calcic. 
It is a transitional variety of pyroxene-andesite related to bandaite. 
The andesite from the rim of the central crater of Iwakisan, in northern 
Hondo, anal. 11, is closely similar to bandaite, with somewhat less 
pyroxene. The rock from the southern summit of Sakurajima, Kyushu, 
anal. 12, which was collected in 1910, before the last great eruption of 
this volcano, is a glassy pyroxene-andesite, having the chemical com- 
position of an andesine-dacite, or shastaite. The hornblende-mica- 
andesite of Mae yama, near Shimabara, anal. 13, and the spherulitic 
dacite from Kosaka, Hondo, anal. 14, are chemically similar, though 
modally quite unlike. They may be classed as shastaites, because of 
the character of their normative feldspars. The glassy dacite, anal. 15, 
from near the Shinyu Inn at the west base of Aso, Kyushu, is a variety 
of ungaite, judging by the norm. The normative plagioclase is oHgo- 
clase, with which is subordinate normative orthoclase. It may be 
classed as an oligoclase-dacite transitional to dellenite. 
Analysis 16 is of a garnet-bearing rhyolitic obsidian, from Hiwashima, 
and analysis 17 is of a spherulitic rhyloitic obsidian said to occur on the 
sea coast north of Kagoshima and Sakarajima. The seventeen analyses 
show that there is a strong chemical likeness among the rocks collected, 
which is well brought out by the norms and magmatic symbols. 
