J. 'J. H. GODFREY ON THE GEOLOGY OE JAPAN. 547 



that these deposits have to be reckoned under the group of meta- 

 morphic rocks. 



Some of the crystalline limestone may be considered useful for 

 ornamental purposes. 



Useful Minerals. — Amongst the useful minerals of Japan are to 

 be mentioned, according to their importance, coal, copper, silver, 

 gold, iron, petroleum, lead, and tin. Of minor importance are sul- 

 phur, antimony, quicksilver, kaolin, and salt. 



(a) Coal. — Under this heading we may distinguish brown coal, 

 fibrous and earthy, and black coal, caking and non-caking. 



The seams of fibrous and earthy brown coal occurring in the 

 Toshibets group of rocks are generally of such limited extent and 

 their quality is so inferior as not to deserve much notice. Next in 

 quality come the coal-deposits along the eastern coast of Nippon, 

 which begin at Skegawa (prov. Iwashiro) and extend in a belt of 

 7| miles width about 30 miles to the north. With occasional in- 

 terruptions, these coal-deposits appear to continue yet for a con- 

 siderable distance (about 200 miles) northwards. The following 

 section has been observed in this district : — 



Clay and sand 15 to 20 feet. 



Coal 6 to 9 „ 



Hard bluish clay 9 feet. 



Coal 1 foot. 



Hard bluish-grey clay 8 feet. 



Coal 1 foot. 



The coal is black and shining, but only the first seam has been 

 worked, and of this usually from one third to one half is left under- 

 ground on account of its being too ashy. Owing to the inferior 

 quality of the coal raised, the working of this deposit has been 

 almost entirely abandoned. 



Towards the north at Kuchi, in the province of Bikuchu, the coal- 

 seams have been found to contain a considerable amount of a dark- 

 coloured amber, which is used for ornaments. 



The most important coal-fields are situated in the Horimui for- 

 mation of the western part of Japan, where the coals assume the 

 character of Carboniferous coal, and most of them are more or less 

 caking. 



The islands in the neighbourhood of Nagasaki, and amongst them 

 prominently Takasima, furnish the best coal yet discovered in Japan ; 

 Takasima coal, as regards its use for steamers, has been proved to 

 be only slightly (about 10 per cent.) inferior to the best Cardiff 

 coals. 



By far the greatest portion of this coal-formation is now covered 

 by the sea, and it is only on these islands that the coal-seams have 

 been upheaved and can be worked. 



The following are sections of the coal-bearing strata at Takasima, 

 Mieke, and Karatsu (the Mieke coal-mines are situated nearly due 

 east, and those of Karatsu to the north of Takasima) : — 



