180 PKE-COLUMBIAN COPPER-MINING 



but two localities where it oonld be obtained in any quantity. These 

 were the Coppermine lliver in the British Possessions, and the Lake 

 Superior copper district. The latter aflbrds the most remarkable occur- 

 rence of native copper in the world, and the present mines on Keweenaw 

 Peninsula — including the famous Calumet and Hecla, the Tamarack, 

 Quincy, and others — are of Avorld-wide fame. The same de])Osits were 

 worked superticiallj^ over their whole extent long- before the advent of 

 Europeans to these shores. 



By referring- to the map of Michigan it will be seen that Keweenaw 

 Peninsula is a prominent geographical feature and extends a consid- 

 erable distance into Lake Superior. Its northwestern shore and the 

 continuation thereof through Ontonagon County is practically parallel 

 to the opposite or north shore of the lake. Through the middle of 

 Keweenaw Point runs a belt of elevated land which is several hundred 

 feet above the lake in some places, and extends from the extreme point 

 through the peninsula and Ontonagon County into Wisconsin. This 

 elevated belt, which is known as tlie "mineral range," sometimes rises 

 Into bluffs which are abrupt on the southeastern or shoreward side, 

 but sloi)ing in the op[)Osite direction or toward the lake. The dip of 

 the formation composing this range (sandstone, and sheets of igneous 

 rock, including conglomerates) is in a general northwesterly direction, 

 or towards the lake and the north shore. On Isle Royale, near the 

 north shore of the lake, the same formation occurs, but dipping in the 

 opposite direction, viz, to the southeast or towards Keweenaw. " Trap" 

 rock carrying copper is also found on the north and east shores of the 

 lake at St. Ignaceand Michipicoten Island. The copper-bearing series 

 of the "mineral range" consists of sheets of igneous rocks — diabase, 

 diabase-amygdaloid, and melaphyr — which include beds of conglom- 

 erate all carrying native copper. Both of these classes of rocks are 

 mined. The famous Calumet and Hecla mine is in tlie conglomerate, 

 as is also the Tamarack, while the Quincy, Atlantic, and others are in 

 the amygdaloid rocks. 



The product of the mines is divided by the miners into three classes, 

 stamp rock, " barrel work," and mass copper. By stamp rock is meant 

 that Mdiich contains the copper in line particles and is sent to the pow- 

 erful steam stamps to be crushed, in order to separate the grains of 

 copper by washing (jigging), just as gold-bearing quartz is stamj)ed. 

 "Barrel work" means the pieces of copper which are large enougli 

 to be detached from the rock without stamping and are packed in 

 barrels and sent directly to the smelters. They vary in size from pieces 

 about as large iis the hand to those not too large to be conveniently 

 packed in barrels. Pieces too large for this constitute the third class, 

 " mass copper," which includes the huge pieces of many tons' weight 

 Avhich are occasionally met with. All this cojiper vshows as such in the 

 rock, and the ancient miners had only to follow down a promising out- 

 croj) showing "barrel work" for a few feet and hammer away the rock 



