230 DESCRIPTIVE MINERALOGY. 



FIBROUS LIMESTONE. 



This variety of calcareous spar is composed of imperfect crystals or fibres, which are either 

 coarse and adhere feebly, or are very delicate and firmly attached to each other, forming solid 

 masses. These fibres are sometimes straight, at others curved, but are mostly parallel. The 

 usual colours are white or grey, often with shades of yellow, red or green. 



LOCALITIES. 



Greene County. Thin veins of fibrous limestone occur at Catskill, which, when polished, 

 resemble satin spar. The same mineral is found in the limestone near Natural bridge, in the 

 town of Diana, Lewis county. 



Onondaga County. At Camillas, this variety of carbonate of lime has been found in con- 

 siderable abundance, and possessing great beauty. Its colours are snow-white, yellow and 

 various shades of brown. It is susceptible of a good polish, both in the direction of, and 

 across, the fibres. It has often, but incorrectly, been called arragonite. Its specific gravity is 

 2.629. It contains no strontia or baryta, as has been supposed. The white variety is a very 

 pure carbonate of lime. The fibres are sometimes nearly two inches in length. 



Orange County. Small veins, having the form and appearance of satin spar, have occa- 

 sionally been found in the slate in this county. Tolerable specimens may be obtained at the 

 quarry near the village of Sugarloaf.* 



Schoharie County. Fibrous limestone is found in the town of Carlisle, seven miles north- 

 west of Schoharie court-house, and near the celebrated locality of fibrous heavy spar. It is 

 white, and usually has the fibres about three-quarters of an inch in length. It sometimes 

 contains a small proportion of heavy spar. Indeed these two minerals seem to pass into each 

 other by almost imperceptible gradations. They can easily be distinguished, however, by the 

 difference in their specific gravity, and by the action of acids. They are both situated in 

 layers between the strata of a soft slate. 



St. Lawrence County. Near De Long's mill, satin spar has been found, with a beautiful 

 lustre, and susceptible of a fine polish. The fibres are curved, and are about half an inch 

 in length. Thin layers of a similar kind occur on the farm of Mr. Streeter, in the town of 

 Rossie, near Caledonia mills. 



Warren County. Carbonate of lime, in short delicate fibres, occurs abundantly in the 

 slate near Glen's-Falls. 



CONCRETED CARBONATE OF LIME. 



Under this may be included all those varieties of carbonate of lime which e.xliibit imitative 

 forms, resulting from the peculiar circumstances under which they have been produced. 

 They are usually composed of a succession of layers nearly or quite parallel, whether straight, 



* Horton. New-York Oeological Reportt, 1839. 



