70 The Limestones, and Lime. [Feb., 



spar was separated and tested was found to be highly magnesian. 

 This limestone was taken from the vicinity of Oxbow, in the 

 town of Antwerp, Jefferson county. It contained also Rensse- 

 laerite, a mineral which has some resemblance to soapstone, 

 though it is considerably harder. The Oxbow variegated or ser- 

 pentine limestone contained 



Insoluble matter, - - - 1.16 



Alumina and peroxide of iron, - - 3. 

 Carbonate of lime and magnesia, - 95.84 



100. 



Limestone of Port Henry, Essex county : color white, crystal- 

 line, with yellow particles, which resemble chrondrodite, and others 

 which are sulphuret of iron. Large masses of calcareous spar 

 are imbedded in the rock at some distance south of the landing, 

 which is a pure carbonate of lime. In the vicinity of the bed at 

 Port Henry, serpentine marble is common, but seems to be dis- 

 connected with the white rock near the iron works. 



Analysis. 

 Insoluble matter, _ - . 

 Carbonate of lime, _ _ _ 

 Carbonate of magnesia, - 

 Peroxide of iron and alumina, 



100. 

 The iron is set down as an oxide, although it is probable it is 

 in the state of a carbonate. 

 Limestone of Putnam count}\ 



Jinalysis. 

 Insoluble matter, _ - - 



Peroxide of iron and alumina, - 

 Carbonate of lime, - - - 

 Carbonate of magnesia, - - - 



It will be observed that the primary limestones are frequently 

 destitute of magnesia, or contain it in very small proportions. 

 They however contain other impurities, such as quartz and other 

 minerals, which injure them for economical purposes, and it is 

 not uncommon to find at least from 50 to 75 per cent of foreign 

 matter in some parts of the beds in Northern New York; but 

 these inferior beds occur usually in patches, and it is rarely the 

 case that good limestone may not be found somewhere upon all 

 the beds or ranges. 



