JEFFERSON COUNTY. :?77 



them. Their geological position is the same, and they furnisli identical facts with the other 

 mines in this immediate neighborhood, and also with those of St. Lawrence coimty. 



i ■ ■ I ■ 



The Sterling Vein. 



This is about three miles south of Somerville in Gouverneur. It is situated in low grounds, 

 and covers a large superficial area. It is enclosed in gneiss ; but within the workings we 

 findthe same associate of the ore, the brecciated serpentine ; and here the imbedded quartz 

 separates easily and distinct!}'', and under circumstances which favor the assumption that the 

 latter mineral was actually inclosed or enveloped in the gneiss while this was in a pasty state. 

 We have no means of determining satisfactorily the state and condition of serpentine previous 

 to consolidation. A state of mud is often spoken of, and the phrase is supposed to express 

 truly what it was ; but the mud must have been composed differently from that of the sedi- 

 ment transported by rivers, which is abraded from rocks, and finally forms the slate and shaly 

 rocks. But though the precise condition of this substance is not understood, yet very little 

 doubt exists but that it was in a semi-fluid state, and was forced upwards through fissures in 

 the superior rock. The masses of quartz in the serpentine at the Sterling mine, separate 

 more perfectly than at the localities where I have noticed the aggregate. At some of these, 

 it would scarcely be suspected that the two substances were ever independent of each other, 

 and that the quartz was accidentally enveloped in the serpentine. 



The characters of the ore at this mine differ in no material respect from those of the Parish 

 and Kearney ores. It is principally the red mass, or the oxide in an earthy state. It is seated 

 rather superficially, or near the surface, and seems to spread more widely than most mines 

 of this description. The ore contains geodes of quartz, sulphuret and carbonate of iron, and 

 calcareous spar. But a more interesting substance which is quite abundant here, resembles 

 Kakoxene. It is golden yellow, and covers the surface of the ore in minute implanted crys- 

 tals, principally occupying the seams. 



Relations of the Potsdam Sandstone in Jefferson County. 

 Principal beds ; limited area ; fractured condition, etc. 



The Potsdam sandstone, in some of its relations, resembles the primary ; it is quite limited, 

 and in many localities where it appears, it is in consequence of the removal of the succeed- 

 ing mass. 



This rock is confined to that part of the county which lies adjacent to St. Lawrence, and 

 upon this border it forms the surface rock as far south as Evans' mills. Its southern boun- 

 dary, however, is by no means formed by a straight east and west line ; on the contrary, it is 

 extremely irregular, and forms an indented border upon the south at its junction with the 

 calciferous sandrock. To trace this border, or line of junction with the latter rock, we may 

 commence about five miles southwest of French creek. From a point, then, at this distance 



Geol. 2d Dist. 48 



