64 ECONOMIC GEOLOGY, 



in the order given. In sucli of the rock thrown out as was visible, they do not occur 

 any of them in large nodules, but scattered in specks through the gangue, and in such 

 form that much would be unavoidably lost in the necessary process of mechanical 

 concentration. A fair average sample, taken from the accessible output of the 

 " Banks shaft," of such rock as would have to be worked, crushed without any separa- 

 tion of ore from gangue, showed, — in the hands of a professional assayer, — gold, o.or 

 oz., silver, 3 oz., to the ton of 2000 lbs. 



Shelburne Lead Mi?ie. About li miles west of Shelburne station, on the Grand 

 Trunk Railway, Lead Mine brook empties into the Androscoggin on the north side. 

 Following up this brook ij miles, a branch comes in from the west through a narrow 

 gorge on the eastern declivity of Mt. Hayes. At the junction of the two brooks are 

 the ruins of ore-separating works, run by water-power, and of three log-cabins. We 

 are here at an elevation of 130 feet above the Androscoggin. Taking the western 

 branch, a further walk of about forty rods brings us to an abrupt turn in the brook at a 

 right angle, the stream coming down over the cliff, which forms the northern wall of 

 the gorge, in a cascade thirty feet high. The mineral vein runs along the bottom of 

 the gorge, much of its course in the very bed of the stream. At the abrupt turn above 

 mentioned the first opportunity to attack it above water-level has been availed of to 

 drive an adit westerly into the mountain upon the vein itself. The adit is 5 feet by 4, 

 and extends about 30 feet. Within a distance of fifteen rods from the adit three shafts 

 have been sunk in the bottom of the narrow gorge, so close to the brook, and their 

 mouths so little above its level, that the most ordinary rise w^ould flood the entire 

 workings. This metalliferous deposit has been worked at several different periods by 

 different companies, and the adit was an after-thought of a later company. One of the 

 shafts is stated to be 80 feet in depth, and another 275, and to have proved the vein 

 eight feet wide at the lowest point reached, carrying in places six inches solid ore. If 

 this be so, the vein at the surface is evidently " a pinch," and the adit could have given 

 no practical vantage without the sinking in it of a winze. At the present not only 

 are the shafts flooded, — they were this probably twenty-four hours after the pumps 

 stopped, — but the floor of the adit is under water, so that it is impossible to learn 

 much of the deposit without a considerable amount of actual work being done. The 

 vein, which is one of segregation, has a strike N. 75° E., and a dip 70° N. 15° W. 

 At its surface its width ranges from two to six inches. The gangue is quartz, which 

 on the hanging-wall is quite pure, while on the foot wall, which is ill defined, it grades 

 into a micaceous gneiss. The chief ore carried is galenite, associated with a very 

 dark blende, and a notable amount of pyrites. The galenite seems to be invariably 

 mixed with these ores, while on the other hand the pyrites occurs in some places unas- 

 sociated. A sample of galenite with pyrites, gave, in the hands of a professional 

 assayer, — gold, none; silver, 15.06 oz. to the ton of 2000 lbs. This ore was almost 

 free from gangue, and may be considered a favorable sample. From the fact that so 

 many parties have worked this, — one of the historical mines of New Hampshire, — 

 always with the result of abandonment, it would seem a fair inference that however 



