122 [SSNATE 



limarCs Journal^ January, 1848.) Massive strontianite is also said to 

 have been found by Mr. James Heron, at "Warwick, in Orange county. 

 Dallas Mineralogy^ 2d ed., p. 254. 



CALCAREOUS SPAR, 

 (Mineralogy of New- York, page 215.) 



Of the crystallized varieties of this mineral, the most interesting 

 localities which have heretofore been found, perhaps, in any part of the 

 world, exist in this State. The finest specimens have been obtained 

 at the mines of Rossie, St. Lawrence county. One gigantic specimen 

 in the cabinet of Prof. B. Silliman, Jr., weighs 165 pounds, and is nearly 

 transparent. Dana's Mineralogy, 2d ed. 



The accompanying cut is the figure of a twin from Rossie, in the col- 

 lection of Mr. Alger, of more than a foot in length. Alger^s PhillipSj 

 page 265. 



Mr. Dana has given a figure of a crystal difiering from any of those 

 contained in my report. See Sill. Jour.^ xlvi. p. 33. 



In regard to the form of the calcareous spar from Rossie, Mr. Ash* 

 mead has remarked, that in reducing specimens to convenient size for 

 the cabinet, he observed that some of the fractured crystals were sus- 

 ceptible of mechanical division in different directions from those of the 

 planes of a rhombohedron. He succeeded in obtaining as a nucleus, a 

 solid, bounded by six isosceles triangular planes, of similar lustre, or two 

 obtuse, three-sided pyramids, placed base to base ; it has but one axis, 

 passing through opposite solid angles ; assuming the axis to be vertical, 

 the base is an equilateral triangle. As the faces are not parallel, but 

 inclined to each other, it is susceptible of perfect cleavage in six direc- 

 tions. 



"The solid angle of the apex is similar to the obtuse solid angle of 

 the rhombohedron, therefore, by truncating the alternate solid angles of 

 the rhombohedron, this solid is produced." Proceedings of the Academy 

 of Nat, Scien. of Phila., Feb. 8, 1848. 



