UME. 



221 



Fig. 77. 



Fig. 76. These crystals have usually only one perfect termination, but this, as 



well as the sides, is highly finished. They are white, translucent or 

 transparent. Twins, or compound crystals of the form represented in 

 Fig. 76, are occasionally met with at Martinsburgh. 



Crystals similar to some of the above have also been found at House- 

 ville and Leyden in this county, and it is probable that most of the modi- 

 fications which I have noticed will hereafter be detected. 



Monroe County. Crystals of calcareous spar, having the form of the 

 metastatique of Haiiy, occur in geodes in the limestone at Rochester and 

 elsewhere. The specimens, however, are far inferior in beauty to those 

 found in Niagara county, which see. 



Montgomery County. There is an unimportant locality of this mineral at the lead mine 

 two miles south of Spraker's basin, on Flat creek. The crystals are sometimes of the hog- 

 tooth form, but they are small and imperfect. Calcareous spar is also found at Flint hill, and 

 it is credited to the town of Florida. The limestone every where contains seams of white 

 calcareous spar, but so far as my observation extends, it rarely exhibits perfect crystalline 

 forms. 



Niagara County. For the beauty and abundance of crystallized cal- 

 careous spar, there is no district in this country which can be compared 

 to that in the vicinity of Lockport. The excavations which have been 

 made for the Erie canal, through the geodiferous limerock, have brought 

 to light geodes of almost all sizes and forms, containing calcareous spar, 

 pearl spar, celestine, selenite, anhydrite, and rarely fluor spar, variously 

 associated and grouped. The individual crystals, however, are usually 

 small ; and it is somewhat singular, that while this mineral is so 

 extremely abundant, there is so little variety in the crystalline forms. 

 The only ones that I have observed are the scalene dodecahedron, meta- 

 statique of Haiiy (Fig. 60) ; and the acute rhombohedron, contrastante 

 of Haiiy (Fig. 77), m on m' 114° 19'; m' on m' 65° 41'. 



In many cases the six additional edges making up the dodecahedron 

 are scarcely visible, the faces of the rhombohedron being merely slightly 

 rounded. I have seen a few crystals of the binaire of Haiiy (Fig. 69). 



The colour of the crystals of calcareous spar found at Lockport is 

 either white or yellowish white, and they are translucent or transparent. 

 They are rarely more than an inch and a half in length. 

 At Niagara falls, and at Lewiston, geodes of calcareous spar have been found similar to 

 those of Lockport, but of far inferior beauty. At the falls, this mineral is sometimes asso- 

 ciated with yellowish crystals of fluor spar, which may have perhaps been mistaken for the 



