GRANITE. 25 



the same ore occurs in this rock in the south part of Dickinson, not far from llic road leading 

 to Duanc. 



In the town of Saranac, there is a reddish granite, which is extensive and important, if tlie 

 locahtics at which it appears arc connected masses. Thus, it forms the gangue of the Skin- 

 ner ore bed, seven miles from Cadyvillc, and three north of Saranac ; and it is probable that 

 it is the same as that which appears twelve miles west of Plattsburgh, on the military road, 

 where it is remarkably traversed by dykes of greenstone. 



Again, beds of this rock occur at Athol and Johnsburgh. At the foot of Crane's mountain, 

 it is the decomposing variety, or that which forms the porcelain clay. Disintegration appears 

 to go on rapidly, and large masses of it may be easily broken into fine pieces. 



The localities I have now given, do not probably embrace all in the Second District ; but 

 they are the most important. In pursumg the beds I have mentioned, I have often found them 

 to assume the character of gneiss, and again the gneiss also as often transformed into granite ; 

 and thus it happens that it is impossible to sa)^ which designation the mass should receive. 

 This fact goes far towards establishing the doctrine that the distinction usually made between 

 granite and gneiss is not one of primary importance, especially in this district. 



I have had occasion already to allude to the association of granite and limestone, and I have 

 attempted to separate this variety, (the one associated with granite and other primary rocks,) 

 by the name of primitive limestone. The occurrence of these two rocks in the same region, 

 gives origin to several varieties of rocks. It is my intention to notice only one in this place ; 

 the others will be described in my account of this limestone in another place. 



I have in view a mass composed principally of feldspar and a magnesian limestone, con- 

 tainino' merely a few lamina of mica. The color of this rock is light grey, on a recent frac- 

 ture ; but brownish, or yellowish brown, when it has been exposed to the weather. It has 

 all the appearance of a granite, arid is quite subject to decomposition. It appears, therefore, 

 in a crumbling condition, in broken masses, or ledges. Where it borders a lake, it forms 

 precipitous, broken and unsafe banks, in which there are numerous large cavities. This 

 variety occurs at Muscolunge lake, where it contains fluor spar, . carbonate of strontian, and 

 pjTritous copper. At " the Bow " in Gouverneur, it is quite an extensive mass, furnishing 

 also p^Titous copper. There is another locality of this rock about four miles from Gouver- 

 neur towards Fowler, on the Oswegatchie. At this place it is somewhat cavernous, and also 

 contains crj'stals of carbonate of lime, sulphate of barytes, and the same ore of copper. 



I have not considered it necessary to determine with precision the extent of this rock, as it 

 gradually passes into the ordinary granite, or into limestone, and is not at all regular in its 

 course or direction. When cliflFs composed of these materials are exposed to some depth, the 

 quantity of calcareous matter in the lower part is greater than above, in a few instances-; but 

 the materials are usually well blended or mixed in most places where it occurs. ' - •"' 



Tliis rock appears to be metalhferous. Sulphate of copper, with sulphuret of iron, in nests 

 and'striiigs, is the most .constant. After much search and examination, however, I believe 

 this rock will not prove valuable as a metal-bearing rock. The quantity is small ; rarely more 

 than one hundred pounds of copper ore has ever been obtained t^X one place. Besides this, 



Geol.- 2d Dist. 4 , 



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