272' ^- ^^To. 



confines of the Abukuraa plateau, as may be judged from a number of 

 specimens which have been brought home from different locahties by 

 my colleagues ; but their modes of occurrence are unfortunately ver}'- 

 little known to me. T. Kochibe^ was the first who acquainted us 

 with the occurrence in the A.bukuma district of a dunite which was then 

 considered as an archsean schistose member. S. Otsuku, however, 

 found it occurring in intrusive dykes within pyroxenites of the 

 palaeozoic age. " It is a compact or fine-granular, dark-green or 

 light-brown rock, essentially built up of olivine, cliromite and a little 

 hypersthene. A fi-esh dunite is only known from Ishigami and Aka- 

 saka-Higashino, near Ishikawa in Iwaki ; and Saimaru, Taga-göri, 

 in Hitachi/" 



I myself collected some specimens from other localities' entirely 

 new to Dr. Harada. One was found as an intrusive boss through 

 a salite-amphibole-tourmaline schist, at Naka-Misaka, and another 

 at Yama-gami, near Takanuki, the latter forming a dyke through a 

 complex of gneiss-mica schist and titanite-amphibohte. The peridotite 

 seems to me from its modes of occurrence to be of a decidedly 

 irruptive origin, injected through various rock-groups of different 

 ages (Profile -1, PL XXIV). But whether there are any near relatives 

 of the peridotite, which might substantially be connected at their root 

 with the olivine rock, or whether it is pressed up alone as dykes 

 through several fissures, quite independent of magmas of other rocks, 

 I am as yet not able to assert definitely. 



It has been known for a long time that basic rocks at their 

 points of contact with others are particularly rich in olivine. Ex- 

 tended researches made by Dr. E. Stecher^ have well shown, how the 

 proximity of the intruded rocks could exercise an influence upon the 



1 T. Harada ; Die japanischen Inseln, p. 75. 



2 Contacterscheinungen an schottischen Ol ivimli abäsen, T. M. M. IX, 1887, p. 146 et seq. 



