2'68 Geology of Lewis County. [May, 



It derives its color principally from the tributaries on the east- 

 ern side, which arise in the swamps of the primary region, and 

 which often contain ores of iron and manganese. The streams 

 that descend from the west are generally limpid, except such as 

 derive their origin from the swamps underlaid by slates and 

 shales. 



The tract of country east of the river, and to a distance vary- 

 ing from one-fourth to one mile to the west, is entirely primitive; 

 being composed of gneiss rock, and constituting the western mar- 

 gin of the great Northern Forest of New-York. The mineral 

 characters of this rock vary but slightly, being composed princi- 

 pally of feldspar, with variable proportions of quartz, hornblende, 

 and particles of magnetic iron ore. 



It usually presents a mottled appearance: but the prevailing 

 color is reddish, or flesh colored. Its texture is coarsely crystaline, 

 and it presents a kind of irregular and confused stratification, 

 with none of that uniform continuity that is observable in strata 

 of sedimentary rocks. The lamina? or strata (if so they may be 

 called) seldom preserve a uniform width, being alternately widen- 

 ed and contracted, or terminated abruptly, and often crossed by 

 irregular and tortuous veins of quartz, apparently the result of 

 segregation. 



We frequently meet with large masses of the constituent mine- 

 rals of the rock, occupying a space by themselves. This is par- 

 ticularly observable at a mine of magnetic iron ore that has been 

 wrought to some extent, in the town of Greig, on the land of 

 Messrs. Johnson and Wardvvell. 



The ore is here inteistratified with the rock, and of sufficient 

 abundance to be wrought with profit, if it could be freed from 

 the iron pyrites that is everywhere uniformly distributed through 

 the ore, and in such quantities as to materially injure if not wholly 

 destroy it in reducing. 



It also yields, upon analysis, a trace of copper. The constitu- 

 ent minerals of the rock appear at this place to have been sepa- 

 rated by their chemical attractions, while the mass was in a yield- 

 ing condition. The amount of ore that exists here has not been 

 determined. The bed seems to widen as it descends; but it is 

 much mixed with the rock, and its siluation is unfavorable for 

 drainage. 



Only a few tons have been raised from the mine, and the work- 

 ing is at present suspended. 



The prevailing direclion of the strata of gneiss in the county 

 is ENE. and WSW., frequently varying several points from this 

 course, and they dip unifoirnly at a very high angle, usually to 

 the north; but in some localities the dip is vertical. At a very 

 few places the dip was observed south. The face of the country 



