38 ECONOMIC GEOLOGY. 



lOO. Excepting occasional blue and green carbonates and the black 

 oxide, any other ores of copper are scarce in this region. The associ- 

 ated ores are argentiferous galena, zinc blende, and an abundance of 

 pyrrhotite, the last named frequently forming beds by itself with slight 

 percentages of copper. All these ores may be auriferous, but to how 

 great an extent remains to be proved. 



The veins are usually situated in broad belts of intermingled pyritifer- 

 ous and siliceous layers, separated by elvans or diorites. The immediate 

 veins may be one, two, or more feet wide, often so close together as to 

 be practically from six to ten feet broad. The ore is in massive, not 

 crystalline bunches, most abundant immediately contiguous to nodules 

 of quartz. Several cases of small veins crossing the strata will be de- 

 scribed in connection with individual mines. Our theory as to the origin 

 of the deposits has been that they were originally beds, not fissure veins ; 

 and that in later periods the copper has been segregated from the gen- 

 eral metalliferous belt into the several strings and veins making up the 

 richest portions. These are found intersected by small cross veins of 

 ore v/ith scarcely any gangue, so that, as the country is exploited more 

 and more, the evidences of the presence of the copper in so-called fissure- 

 lodes increase. 



I have thought the continuity of the vein is to be seen in the 

 presence of a series of lenticular patches or bonanzas, not succeeding 

 each other on absolutely the same plane, but overlapping. On this view, 

 what seems to be the same vein in adjacent lots is rather a series of 

 flattened bunches, working more and more to one side. I have not yet 

 discovered irregularities in the veins on Gardner mountain correspond- 

 ing in magnitude with those of the auriferous conglomerate in the south- 

 east part of the town, though only exploration is needed to develop them. 



I will now describe the features of the several mines in detail. 



Gardner Mountam Copper Company. This property consists of 250 acres of land 

 held in fee simple, a farm-house with the usual outbuildings, and the improvements 

 effected for mining purposes. Much of the land has been cleared, a part remaining 

 wooded. It has been known heretofore as the Albee mine, from its former owner, J. 

 A. Albee. The principal outcrops are on a hill several hundred feet above the Con- 

 necticut, sloping northerly. The eastern slope is precipitous. The veins arc hence 

 well situated for exploration by cross-cuts, or through a drift following the course of the 



