1884.] 205 [Wadsworth. 



sandstone are intercalated beds of red shale, some of which is 

 of so fine a quality that it has been used as a mineral paint. All 

 these rocks dip N. 20° E. 26°. The ore is in nodules and lentic- 

 ular masses composed of chalcocite or its hydrous carbonate (mala- 

 chite) scattered through the beds of sandstone and shale. It 

 is so associated with the carbonaceous materials in the rocks, that 

 it is believed that the copper was collected by the percolating wa- 

 ters, precipitated and reduced by the organic matter, and thus col- 

 lected into the masses found at present, many of which are now in ■ 

 part lignite and in part chalcocite. The change to the carbonate 

 is, of course, a still further change, wrought through the medium 

 of the percolating waters. 1 



ZINC. 



During the mining excitement in Maine, in 1879-82, a mine was 

 opened in the town of Castine, Hancock County, known as the 

 Hercules. The country rock is a fine grained mica schist, much 

 indurated and quartzose. In places it approaches, in character, 

 quartz schist, and in others, a gneiss. The rock contains, in places, 

 abundant pyrites. The dip and strike are variable, the former 

 varying from south to 30° or 40° west, with an inclination of 75° 

 to 81°. The country rock is traversed by small quartzose veins, 

 carrying pyrite and sometimes sphalerite and it is more or 

 less broken and jointed, part of the jointing being parallel to the 

 foliation. When the jointings cross one another oblique^ and 

 also when parallel, if sufficiently close together, so that the rock has 

 been crushed or finely divided, the percolating waters have deposit- 

 ed in the interstices more or less zinc-blende, iron pyrites, galena, 

 tremolite and quartz, which in part replace the rock material. 

 This segregating action of percolating waters thus gave rise to the 

 local aggregations of mineral matter in the form of impregnations 

 of the country rock, and of segregated veins. So far as the writer 

 can learn, the above deposit is a fair sample of the majority of 

 those heretofore worked in Maine. 



GOLD. 



Another of the Maine mines was on Seward's Island, town of 



1 Gesner's Remarks on the Geology and Mineralogy of Nova Scotia, pp. 139, 140; 

 Am. Journ. Sci. 1828 (1), xv, 151-153; Trans. Am. Acad., 1831 (2), I, 289-292; Dawson's 

 Acadian Geology, third editon, pp. 315, 346; Report of the Department of Mines of 

 Nova Scotia, 1876, p. 63; 1877, pp.48, 49; 1879, p. 13; 1880, pp. 75-77. 



