262 



DESCRIPTIVE MINERALOGY. 



They frequently contain specks and small masses of a black substance, which is believed to 

 be anthracite. Its behaviour before the blowpipe agrees entirely with that mineral. Some- 

 times these crystals have cavities, which are partly fiUed with some fluid. When these have 

 been shivered by the cold, the cavities present a yellow resinous appearance, from which it 

 may be inferred that the liquid is bituminous. From the number of fragments which present 

 this appearance, it is probable that the crystals containing this liquid were originally very 

 abundant. 



At Little-Falls, the quartz crystals are usually contained in cavities in the calciferous sand- 

 stone, and it is not uncommon to find them imbedded in the powder of the anthracite. 



The crystals from Salisbury are larger than those from any other locality in the county, 

 but they have seldom been obtained so perfect as at Middleville. Here also large masses of 

 anthracite were found associated with the quartz. The crystals from this locality are some- 

 times from four to si.x inches in length. 



At all the above localities, twin crystals, and groups of crystals variously united, have been 

 found. Middleville, however, is the most remarkable in this respect. Crystals of quartz, 

 usuially small, are also often found lining the walls of the cavities which contain the loose 

 crystals. 



It is proper to state, that the occurrence of quartz crystals in such abundance in this county 

 was first made known to the public by Prof. J. Hadley, of the Geneva Medical College.* 



Among the vast number of crystals which have been obtained in this county, it is not sur- 

 prising that various and rare forms sometimes occur. From some hundreds which I have 

 examined, the following are selected as more or less interesting, viz : 



Figs. 130, 131, 132, 133, already introduced ; and Figs. 141, 142, 143, 144, 145, 146, 147, 

 and the twin 148, from Little-Falls. 



Fig. ui. 



Fig. 142. 



Fig. 143. 



Fig. 144. 



• Nac-York Medical and Physical Journal. II. 132. 



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