J. G. H. GODFREY ON THE GEOLOGY OF JAPAN. 551 



the present day. Two of these lodes are parallel to each other and 

 bear from E. to "W. ; the average dip of the first is 65° S., and of 

 the second 65° N". Their width varies from 3 to 25 feet, and the 

 metalliferous portion of the veinstuff consists of silver-glance, ar- 

 senical and antimonial silver, an alloy of gold and silver, copper- and 

 iron-pyrites, blende, and occasionally galena. One of these lodes 

 (Torigoi) is rich in sulphuretted ores, whilst the other (Aoban) is 

 comparatively free of them, and at the same time richer in gold and 

 silver. Of the first lode a length of 5500 feet to a depth of 400 feet 

 below adit-level, and of the second about 2500 feet on the bearing 

 700 feet below adit-level, have been mined, but the intersection of 

 these two lodes has not been reached yet. The third lode (Hiakumai) 

 runsfromN.N.E.toS.S.W.,withadip of about 35° to the S.S.E. 

 The width of this lode varies considerably, but only 3 feet of it 

 in the hanging wall are mined. The veinstuff is similarly com- 

 posed to that of the first-mentioned two lodes, but contains here 

 scarcely any gold. Ehyolite, which sometimes changes into a variety 

 resembling felsite, is the containing rock of all three lodes. 



In the province of Ugo, at the Innai mine, one lode of an average 

 width of from 4 to 5 feet, bearing E. to W., and dipping slightly to the 

 N., occurs in a felsite belonging to the old volcanic rocks. The 

 veinstuff consists of silver-glance, antimonial silver, copper-pyrites, 

 and blende ; the gangue is chiefly quartz, occasionally calcite. The 

 greatest depth reached below adit-level amounts to 700 feet ; but the 

 extent to which this lode has been worked on the strike is not 

 known. 



A peculiar and interesting occurrence of silver-ore is that at the 

 Kosaka mine (prov. Eikuchu). Irregular deposits of silver-ore are 

 found there in a green felspathic porphyry, generally wherever 

 this rock becomes friable or decomposed. The ore resembles an 

 earth or sand, and consists of about 80 per cent, of silica, gypsum 

 in small quantities, and silver probably in a state of sulphide. 

 When richest in silver, this ore has a yellowish or reddish-grey 

 colour. A poorer ore of a black colour (being an intimate mixture 

 of quartz, gypsum, argentite, blende, galena, copper- and iron- 

 pyrites) is found in pockets in close contact with the unaltered con- 

 taining rock. Both these deposits appear to be confined to a certain 

 zone about 150 feet in depth. 



The quartz-lodes which are mined at Ikuno (prov. Tajima) run 

 nearly S.E. to N.W., with a nearly vertical slightly northerly dip. 

 They occur in rhyolite and contain silver-ores (argentite and anti- 

 monial silver) rich in gold (about 12 per cent, in the bullion pro- 

 duced). Their width varies considerably from less than a foot to 

 15 feet. The workings on these lodes are yet comparatively 

 shallow. 



At the Takaiyama mines (prov. Hida) numerous small veins con- 

 taining silver-ores and galena, usually bearing N.E. to S.W., occur 

 in a granite which, in the neighbourhood of the mines, changes into 

 a felsite. 



