OKIGIN AND FOUMATIOX OF SOILS. 115 



Analcime. Chabasite. Natrolite. Scoi.ecite. Thomsokite. 



Lake Superior. Nova Scotia. Bergen Hill, Ghaut's Tun- Magnet 



N. J. nel, India. Cove, Ark. 



C. T. Jackson. Rammelsberg. Brush. P. Collier. Smith & Brush, 



Silica, 53.40 52.14 47.31 45.80 36.85 



Alumina, 22.40 19.14 26.77 25.55 28.42 



Potash, 0.98 0.35 0.30 



Soda, 8.52 0.71 15.44 0.17 3.91 



Lime, 3.00 7.84 0.41 13.97 13.95 



Magnesia, ■ 



Sesquioxide j 52 ^ 



of iron. 



Water, 9.70 19.19 9. at 14.28 13.80 



Stilbite. Apophyi.lite. Pectolite. Laumontite. Leonhardite 



Nova Scotia. Lake Superior. Bergen Hill. Phippsburgh, Me. Lake Sup'r 



S.W. Johnson. J. L.Smith. J. D. Whitney. DuWnoy. Barnes. 



Silica, 57.63 52.08 55.60 51.98 55.04 



Alumina, 16.17 1.45 21.12 22.34 



Potash, 4.93 



Soda, 1.55 8.89 



Lime, 8.08 25.30 32.80 11.71 10.64 



Water, 16.07 15.92 2.96 15.05 11.93 



€alcite, or Carbonate of Lime, CaO CO^, exists in na- 

 ture in immense quantities as a mineral and rock. Mar- 

 ble, chalk, coral, limestone in numberless varieties, consist 

 of this substance in a greater or less state of purity. 



Magnesite, or CurhonatQ of 31(Agiiesia, MgO C0„, oc- 

 curs to a limited extent as a white massive or crystallized 

 mineral, resembling carbonate of lime. 



Dolomite, CaO C0„ + MgO C'0„, is a compound of car- 

 bonate of lime with carbonate of magnesia in Aariable 

 proportions. It is found as a crystallized mineral, and is 

 a very common rock, many so-called marbles and lime- 

 stones consisting of or containing this mineral. 



Gypsum, orllydrous Sulphate of Lime, CaO SO^ + Wfi^ 

 is a mineral that is widely distril)uted and quite abundant 

 in nature. When "boiled" to expel the water it is 

 Plaster of Paris. 



Pyrites, or liisulphide of Iron, Fe S„, a yellow shining 

 mineral often found in cubic or octahedral crystals, and 

 frequently mistaken for gold (hence called fool's gold), 



