J. G. H. GODFREY ON THE GEOLOGY OF JAPAN. 



553 



distance of about 12 English miles, and their extension in depth 

 has on several points been proved to amount to about 1200 feet. 

 These deposits are composed of (1) magnetic iron-ore, often possess- 

 ing polarity, varying from 4-6 to 4-9 in specific gravity according to 

 its compactness; (2) garnet, often in well-defined crystals; (3) 

 epidote in groups of thin and tall crystals ; (4) another green 

 mineral, probably chlorite ; (5) iron- and copper-pyrites, fortunately 

 confined to certain parts of the deposits ; (6) malachite and azurite, 

 as a thin coating or exfoliation of rare occurrence. 



The following analysis will show the composition of the ore at 

 various points : — 



Water 



Silica 



Protoxide of iron 



Sesqiuoxide of iron 



Alumina 



Protoxide of manganese 



Lime . 



Magnesia 



Sulphur 



Phosphoric acid 



Metallic iron 



0-50 



6-28 



11-84 



69-34 



9-89 



0-35 



1-17 



0-34 



trace. 



0-19 



99-90 



57-75 



2. 



0-16 



7-05 



22-26 



54-15 



13-14 



0-18 



2-50 



0-50 



009 



0-00 



100-03 

 55*23 



007 



7'90 



24-40 



57-20 



4-48 



0-15 



4-17 



1-42 



trace. 



0-10 



99-89 

 5904 



0-22 



18-42 



2109 



52-53 



4-30 



0-29 



1-74 



0-93 



007 



trace. 



99-59 

 53-18 



5 a. 5 6. 



1-52 



13-42 



13-60 



5904 



5-51 



015 



6-09 



0-20 



0-08 



trace. 



99-61 

 51-93 



0-91 



12-35 



13-97 



62-28 



767 



0-27 



2-18 



007 



0-18 



000 



54-47 



No. 1. 

 No. 2. 

 No. 3. 



No. 4. 



No. 5 a. 

 No. 5 b. 



Average sample from Ohashi Maeyama. 

 „ Shinyama. 

 Sahinai Motoyama. 

 Ohashi Taremizu. 

 Sawahi Motoyama, 



upper, 

 lower. 



The containing rock of these magnetic iron-ore deposits changes con- 

 siderably. Towards the east it usually consists of a felsite composed 

 of orthoclase and quartz, which gradually changes into a felspathic 

 porphyry. On the western side this rock disappears and is replaced 

 by a diorite, often showing large crystals of hornblende. In the 

 north-western part of the mountain-ridge chiefly granitic rocks are 

 found ; sometimes a crystalline limestone forms one of the enclosing- 

 walls of these deposits. 



The formation in which these deposits occur may, in my opinion, 

 be considered metamorphic. Future explorations yet have to prove 

 whether the numerous deposits of the same bearing found within a 

 distance of about 2 miles from E. to W. are parallel deposits or per- 

 haps only spurs or branches of one main or champion mass. 



Deposits of magnetic iron- ore of a similar character but of less 

 magnitude are found in several other provinces of Japan, as Iwaki, 

 Harima, Hoki, Hiuga, and Satsuma. 



Other iron-ores, as specular iron, brown and red haematite, clay 



