Analysis of Limestone, 111 



ing matter was black hornblende, sometimes in streaks 

 or veins, sometimes minutely divided and mixed with 

 .the limestone, giving the greyish tinge to the stone. 

 The 9th specimen was intermixed with mica ; the in- 

 soluble residuum of the four first specimens in dilute 

 marine acid contained a small portion of matter, silky 

 to the touch. I believe all the limestones connected 

 with the range of primitive formations on the seaboard 

 of our country from Boston to Virginia contain more 

 or less of magnesia. They are in the immediate neigh- 

 bourhood of the steatite and other magnesian strata, 

 that envelope as a matrix, the chromat of iron. I tried 

 the specific gravity of three of them, which varied from 

 2,65 to 2,72 the usual range of common limestones. 



No. 1. Holstein^s .'Colour, greyish white : Fracture, 

 uneven : Surface, common splintery : the stone seems 

 to consist of minute lustrous chrystals : slightly fetid 

 on being pounded. I obtained in 100 parts, silex 3, 

 alumina 2, carbonat of magnesia 12. The rest was 

 carbonat of lime or pure limestone. The traces of iron 

 were evident with tincture of galls and prussiat of pot- 

 ash, but in no greater degree than might be attributed 

 to the usual impurity of the acids of commerce. Mv 

 muriatic acid was freed from the sulphuric, by muriat 

 of Baryt. 



No. 2. Coatesh. Colour, greyish white : Fracture, 

 uneven : Surface, fine splintery, consisting of minute 

 sparkling chrystals. I obtained in 100 parts, of silex 3, 

 alumina 2, carbonat of magnesia 14. The rest was 

 pure limestone. 



No. 3. Yoeum^s. Colour, greyish white streaked with 

 blueish grey, being coloured W'lth hornblende (amphi- 



