LINDOREN.] IDAHO CITY GOLD BELT. 687 



only in the narrow seams, and as the ground was very soft and heavy, 

 square timbering had to be used. Underground the vein appears to 

 strike N. 20 W., from which disagreement with the surface strike it 

 would appear that the vein has been considerably disturbed. A nar- 

 row vein in the hanging wall of the big deposit was mined during 

 189G and furnished small quantities of very rich ore. This was not 

 much decomposed, and indicated what the character of the ore will 

 be in depth. It contained bunches of pyrite," arsenopyrite, and 

 blende, with a gangue of quartz and some calcite. The fresh sul- 

 phurets contained much coarse gold, the ore being free milling to 70 

 per cent of its value. It is probable that most of the vein in the 

 Crambrinus mining district will remain largely free milling as depth 

 is attained. The value of the coarse gold in the sulphurets is $15 to 

 $10. The fineness of the amalgamated bullion is 680 to 718. 



Mona MacCarthy is the name of a small vein located three-fourths 

 of a mile west of the Boulder, on the high side, and lying between the 

 Boulder and the Forest King veins. Some work has been done on it. 

 Many small seams are found between this vein and the Forest King. 



The Sub-Rosa or Forest King vein. This vein is traceable for a 

 distance of 2 miles from the Washington mine on the east to beyond 

 the Forest King on the west. It crops in hard granite throughout, 

 though at several places dark-green, dioritic dikes appear near it or 

 cross it. Though narrower than the Illinois and the Gambrinus, it 

 has produced some good pay shoots. 



The Forest King was located in 1875, and a 10-stamp mill was erected 

 on it in 1884. The elevation of the mill is 6,280 feet. The United 

 States mineral monument of the district is indicated by an iron rod in 

 an outcrop close by. No work has been done on the vein during the 

 last few years. The vein shows on the surface in quartzose crop- 

 pings, which do not contain any pay. It is opened by a tunnel 900 

 feet long, through granite, which shows several seams dipping south- 

 ward. The vein consists of a zone, several feet wide, of crushed gran- 

 ite with smaller quartz seams. It strikes N. 56 W., and dips 60 S. 

 The drift on the vein extends several hundred feet east and west. 

 Three hundred feet west a dike, 20 feet w T ide, of a dark, syenitic rock 

 (probably a minette) apparently cuts across the vein ; but from the 

 fact that the dike is full of small quartz seams, which all contain a 

 little gold, it is probable that the dike is really older than the vein, 

 and that the difference in appearance of the vein in the two rocks is 

 due to the difference in their resistance to the dislocating force. A 

 dike of the same rock, 1 foot wide, occurs in the crosscut, and is par- 

 allel to the vein in dip and strike. A 50-foot winze was sunk below 

 the tunnel level, some distance west of the crosscut, in the bottom of 

 which was found altered granite, with sulphurets and small quartz 

 seams, giving assay values of $80 to $100 per ton. 



A location called the Northern Light, on which some work has been 



