GRANITE. 



23 



Classification of the Primary Rocks, comprehending those only ivhich have been observed in 



the Northern District. 



I. UXSTRATIFIED. 



1. Granite; 



2. Hypersthene Rock ; 



3. Primitive Limestone; 



4. Serpentine; 



5. Eensselaerite. 



I. PRIMARY. 



H. Stratified. 



1. Gneiss; 



2. Hornblende; 



3. Sienite ; 



4. Talc, or Steatite. 



III. Sl'BORBINATE. 



1. Porphyry; 



2. Trap; 



3. Magnetic, and 



4. Specular Uxide ol' Iron. 



It is proper to observe, in relation to some of the rocks I have placed in the above Table, 

 that it is not usual to describe thcin as rocks at all, but rather as minerals ; this is the case 

 with rensselaerite, and magnetic and specular oxides of iron. In consideration of their occur- 

 ing, however, in e.xtensivc masses and beds as well as veins, they appear to be well entitled to 

 the appellation of rocks, and I have therefore placed them in the list. Another curious and 

 interesting fact will appear from an examination of the preceding list, viz. that mica and tal- 

 cose slate rocks, which are so constantly the associates of gneiss and hornblende, are totally 

 wanting in this district. In the Primary districts of New-England, they form the principal 

 rocks. There are, also, other differences between the two districts, the principal ones arc to 

 be found in the granites and limestones, and especially in the remarkable devclopement of the 

 mass which I have termed hypersthene rock. Those differences will form subjects of remark 

 when the rocks are under consideration. 



1. Granite. 



Remarkable as the assertion may appear, still, I beheve it to be true, that the granite of the 

 Northern District is not only a rock of small extent, but is also one of the least importance ; 

 for, so far as observation may be relied upon, it is very rarely connected with mineral depo- 

 sites, or associated with any degree of regularity with the metallic compounds. 



The granite of the Second District is found in limited patches, forming the surface rock in 

 areas which it is impossible to define or bound ; it is quite irregular in its appearance, and is 

 so uncertain in its continuance at the surface, that I shall not attempt to define its extent, ex- 

 cept in a few instances. I propose to give merely the principal localities, inasmuch as the 

 area and the extent, so far as it has been traced, can rarely be determined with any degree of 

 precision. 



I shall commence the topographical account of granite at Fowler, St. Lawrence county ; 

 giving the most important locahties on the St. Lawrence side of the district, when I shall close 

 by those upon the Champlain side. Near Halesborough, in the town of Fowler, is one of the 

 largest beds of granite in the county ; it extends to Little York ; it is about six miles long, 

 and presents nothing worthy of notice, Iseing the usual variety. It contains imperfect crys- 

 tals of garnet and schorl. At Halesborough, it embraces a mass of coarse while limestone. 



