DR. BUNDJIRO KOTO ON SOME JAPANESE ROCKS. 447 
Usiti pass opposite to the Midgi-San was analysed by O. Korschelt*, 
who obtained the following results :— 
SIO) acct serge eee ne oe 
1s 0 PPM S A Trn yta ceca 8 Oe 20°42 
12/0 0 Sn e Scea a 6°44 
AOR. oc, «in 3 Sessa say eRe 8°33 
ULC OURO rr, foc C5 RT 3°79 
EN ORs... cz! «ky nas Wace ee 5°74 
OCR i oe... oicla Stepan 1:90 
102-37 
The rock from Kanatake, in the province Kozuke, has a black 
glassy appearance and resembles that from Podhrad in Hungary. 
Under the microscope the ground-mass is seen to consist of glassy 
plagioclase in lath-shaped crystals, augite and grains of magnetite 
imbedded in a coffee-brown glass-basis very rich in augite belonites. 
The minute acicular bodies and spicular forms are gathered together 
in confused aggregations, and in some instances large augite micro- 
liths are bordered by incipient crystals forming plumose tufts like 
the feather of an arrow; the glass-basis around them is decolorized. 
In the rock from Kimimasu the components are of the normal type, 
except that the ground-mass has a spotted appearance caused by the 
irregular distribution of the glass leaving white spots in the mass. 
The spots are due to the aggregation of almost colourless, very 
minute augite microliths and a few felspar crystals. The remainder 
consists of the brown glass-basis with a few augite microliths. 
ENSTATITE-ANDESITES. 
One of the enstatite-andesites occurs in Kokaze in Izu. Itisa 
blackish-green rock and coarsely porphyritic. Enstatite, plagioclase, 
and augite are porphyritically imbedded in the ground-mass. The 
enstatite is not fresh, and consists of a green fibrous substance, the 
fibres lying parallel to c¢. It is dichroic; parallel to ¢ it is sea- 
green; normal to ¢, reddish brown. Extinction is parallel to the 
crystallographic axis. Apatite with liquid-enclosures occurs in 
this rhombic pyroxene, and calespar in the lenticular interspaces 
between the fibres of the enstatite. Pleochroic, fresh, monoclinic 
augite is present, and also plagioclase. The ground-mass consists of 
felspar and augite microliths with a little magnetite, which by their 
arrangement show the so-called microfluctuation-structure. 
Another enstatite-andesite occurs in Nawatsi. It is of a dark 
colour and contains the columnar enstatite; it is of the same 
character as that just described. When the enstatite is further 
decomposed, the fibrous substance is removed and is entirely 
replaced by calcspar. The latter is exceedingly rich in liquid- 
.* Transactions of the Asiatic Society of Japan, 1880. E. Kinch, “ Contribu- 
tion to the Agricultural Chemistry of Japan,” p. 381. 
, : 2H 2 
