208 



DESCRIPTIVE MINERALOGY. 



Fig. 36. 



It should be stated, that minute dnisy crystals of heavy 

 spar occur in the water limestone at Schoharie. The ac- 

 companying figure 36, the hinaire of Haiiy, is introduced on 

 the authority of Prof. Shepard. This mineral is also found in 

 rhombic tables of a dark bluish grey colour, forming the bed 

 of cubic crystals of iron pyrites, about a mile west of the 

 court-house. It, moreover, occurs in laminae running through 

 the septaria which abound in the creek near Boyd's mill, in the town of Middleburgh. In 

 these cases, it is usually of a bluish colour, and may easily be reduced by cleavage to the 

 primary form. 



St. Lawrence County. There are various localities of heavy spar in this county. In the 

 town of Hammond, the crested variety occurs of a snow-white colour, and containing crystals 



of iron pyrites. Large crystals are found in the town of De 

 Kalb. In the town of Fowler, tabular crystals are associated 

 with specular iron ore. At the Parish ore bed, it accompanies 

 calcareous spar in small geodes in the specular iron, and is found 

 in tabular crystals having the primary form, with the acute edges 

 replaced by two new sides, the raccourcie of Haiiy. Fig 37. 

 P on A 90° ; M on A; 129° 13' 54''. 

 This mineral also occurs in flattened crystals, variously modified, on the bank of Laidlaw 

 lake, in the town of Rossie, where it is associated with limpid quartz, calcareous spar, and 

 rarely fluor spar. These minerals are in a vein in the primary rock. The heavy spar is in 

 implanted crystals, of a white or reddish-white colour, and is translucent or opaque. These 

 crystals are sometimes two inches or more in length. The following forms have been observed 

 at this locality : 



Fig. 38. Fig. 39. 



Fig. 37. 



Fig. 38. The trapezienne of Hauy. 



Fig. 39. The same, with one of the faces d 

 much enlarged. 



