126 



A novelty in the occurrence of calcareous spar, is the recent discovery 

 of groups of crystals in the form of flat, six-sided tables, of various 

 sizes, from half an inch to two inches in diameter. These crystals 

 have been found in the coarse granite near St. Anthony's Nose, on the 

 Hudson river, during the excavations for the railroad on the banks of 

 that stream. THe accompanying cuts are drawn from a specimen pre- 

 sented to the State Cabinet by John E. Henry, which is one of the best 

 that I have seen from that locality. It is more than a foot in length and 

 breadth. I have received several fine specimens from Mr. Cyrus Foun- 

 tain, of Peekskill, who has been for several years actively engaged in 

 collecting the minerals of Westchester and Putnam counties ; and to 

 whom I acknowledge myself indebted for many interesting facts, which 

 he has from time to time communicated. 



In addition to the numerous forms heretofore figured from Tompkins 

 quarry, in Rockland county, several others may be added, as having 

 been found at that locality. Among these are the dodecacdre, of Haiiy, 

 (Fig. 71, of the Mineralogy of New-York,) and several of its modifica- 

 tions. Also a twin of the same form, represented in the annexed figure. 

 In other crystals, the solid angle of a rhombohedrom passes through the 

 terminal planes of a six-sided prism. 



DOLOMITE. 



The following mode of distinguishing between dolomite and carbo- 

 nate of lime, is proposed by M. Zehmen : Pulverize a small quantity 

 of the mineral, and subject it to the heat of a common alcohol lamp, in 

 a pktinum spoon. The carbonate of lime acquires, by this treatment, 

 a certain degree of coherence ; while the powder of dolomite, which 

 loses carbonic acid, remains without coherence. Berzelius' Report for 

 1847. 



