26 GEOLOCiY OF THE SECOND DISTRICT. 



the quantity of pure pj'ritous copper varies in the same mass, the latter frequently changing 

 into pvritous iron. 



The origin of this rock, I apprehend, is precisely the same as that of all the granitic com- 

 pounds. It is not, as some perhaps would be ready to suggest, produced by the overflowing 

 of a moulten mass of granite on a sedimentary limestone, thereby decomposing it ; and by 

 which, portions the most intensely acted upon would be raised in a vaporous state, and made 

 to penetrate the mass of cooling granite above. Geologists, in speaking of limestone, seem 

 to be aver.se to the admission that it may form a portion of the interior of the earth, or even 

 to admit that it may exist there at all ; but there seems not a particle of sound reason against 

 the doctrine that it may be as common in the earth as silex, or any of the simple or compound 

 rocks. There is, in fact, more reason to make this inference ; for many of the phenomena of 

 nature speak of its being, and proclaim its existence. From what I have seen of it, I am 

 disposed to consider it as one of the igneous products, having its origin in a mode correspond- 

 ing to all the unstratified rocks, and differing from them merely in the materials of which 

 it is composed. Tlie calcareous matter disintegrates more rapidly than the feldspar ; and 

 hence it is common to meet with this rock presenting a spongy appearance, or fuU of small 

 uneven cavities. These cavities are frequently green, from a slight stain of carbonate of 

 copper, which has also been formed from the sulphuret by decomposition. 



The granite of the northern division of the State occupies almost exclusively the lower 

 portions of the primary districts, and it never forms the mountainous ranges. It is confined 

 to the valleys, particularly that variety which is associated in St. Lawrence county with lime- 

 stone. In Essex and Clinton counties, the gTanitic ranges are more elevated ; but still this 

 rock is confined to the hills or mountains of moderate height. 



The agricultural characters of the granitic districts are apparently uninfluenced by this 

 rock. The soil is never derived from it in a proportion which can affect at all its products 

 either for good or bad. The variety which is composed of so large a quantity of carbonate 

 of lime, decomposes rapidly, and forms, so far as it goes, an excellent material for cultivation. 



