146 



figured ; but those which are here introduced are worthy of notice. 

 They are of the actual size, and from one-third to one-half an inch in 

 thickness. 



Dr. Leonard informs me that next to the six hemitropes, the most 

 common combination is that of two united by their apexes. 



Specimens of columbite have been found by Dr. Leonard, associated 

 with chrysoberyl, at the Greenfield locality. 



Descloizeaux has published under the crystaline forms of cymophane, 

 a detailed description, with plates, and M. Biot has made some experi- 

 ments upon the structure of this mineral in regard to polarized light. 

 ^7272. de Chim, et de Phys. xiii, 329, 335. 



ORDER IV. ZIRCONIA. 



ZIRCONITE. 



(Mineralogy of New- York, page 378.) 



This mineral has been found in New Sweden, Essex county, (Em- 

 mons* Rep. Geol., 2d Dist., p. 2S6 ;) Putnam Valley, Putnam county, 

 (Fountain ;) and on the farm of Mr. Cleaveland in Diana, Lewis county. 

 At the latter locality it occurs rarely, but the crystals, although small, 

 are very brilliant. F. B. Hough, who quotes Mr. Wilder, Sill. Jour., 

 Jan., 1S48. 



I have also received specimens from Mr. Charles Thomas, which 

 were obtained from a mine of magnetic iron ore, near Port Henry, Es- 

 sex county. In form and color the crystals resemble those from the 

 Hall mine in the same county. 



