GE^OIvOGY hA SAIyTvE COUNTY. 



71 



Gypsum, 654; sulphate of lime, plaster of paris, 

 plaster; sulphuric acid, 46.5; lime, 32.6; water, 20.9; 

 massive or crystallized; g-listenin^ white to dull; of 

 various shades; g-ranular, like loaf sug'ar; fibrous, as 

 if made up of fine threads or in flat, beveled-edg-ed crys- 

 tals, g"enerally somewhat rhomboidal, or in slender 

 nodules. We have the cr3^stallized form; selenite, 

 often tinored with iron, scattered through the clays 

 above and below the coal, also the fibrous or satin spar 

 forming a thin bed under coal No. 2 at Ottawa and in 

 other places. 



Melanterite, 664; sulphuric acid, 28.8; iron, 25.9; 

 water, 45.3; in powder, in stalactitic forms; greenish 

 white to white, becoming yellow; soft; has a puckery, 

 sweetish taste. Found on the rocks in coal diggings 

 and on the timbers as thin crusts, small stalactites, 

 etc. Formed by decomposition of pyrite or marcasite. 



Calcite, 715; carbonate of lime, limestone; car- 

 bonic acid, 44; lime, 56; massive in thick beds or crys- 

 tallized: usuall}^ gfray or yellowish gray, bluish or 

 brownish or crystallized, and white and glistening, 

 often streaked, with black and other colors. The 

 crystalline varieties are called marble; crystals, six- 

 sided pyramids, flattened pyramids, rhombohedrons, or 

 more or less close approaches to a cube, etc. The 

 rhombohedral form is very common in the veins of 

 crystals in the Trenton, the pyramidal in the coal 

 measure concretions of the Big Vermillion. Stalag- 

 mite and stalactite occurs in crevices of the limestone 

 at La Salle. 



Calcareous tufa, a deposit from waters carrying* 

 much lime in solution, incrusting, not petrifying, 

 mosses, grass, twigs, etc., and sometimes forming 

 sheets over the face of a rock occur in Clark's Run s,t 

 Utica and farther up that stream, and in many other 

 places. 



