ORIGIN AND FORMATION OF SOILS. 115 
ANALCIME. CHABASITE. NATROLITE. -SCOLECITE. THOMSONITE. 
Lake Superior. Nova Scotia. Bergen Hill, Ghaut’s Tun- Magnet 
N.J. nel, India. Cove, Ark. 
C. T. Jackson. Rammhelsberg. Brush. P. Collier. Smith & Brush, 
Silica, 53.40 52.14 47.31 45.80 36.85 
Alumina, 22.40 19.14 26.7 25.55 20.42 
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 ee = — 1.55 
of iron, : 
" Water, 9.70 19.19 9.84 14.28 18.80 
SrmsiteE. APOPHYLLITE. PEcTOLITE. LAUMONTITE. LEONHARDITE. 
Nova Scotia. Lake Superior. Bergen Hill. Phippsburgh, Me. Lake Sup’r. 
S.W. Johnson. J.L. Smith. J.D. Whitney. Dufrénoy. Barnes. 
Silica, 57.63 52.08 55.66 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 “82.86 11.71 10.64 
Water, 16.07 15.92 2.96 15.05 11.93 
Calcite, 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 Carbonate of Magnesia, MgO CO,, oc- 
curs to a limited extent as a white massive or crystallized 
mineral, resembling carbonate of lime. 
Dolomite, CaO CO, + MgO CO,, is a compound of car- 
bonate of lime with carbonate of magnesia in variable 
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, or Hydrous Sulphate of Lime; CaO SO, + H,0, 
is a mineral that is widely distributed and quite abundant: 
in nature. When “boiled” to expel the water it is 
Plaster of Paris. 
Pyrites, or Bisulphide of Iron, Fe §,, a yellow shining 
mineral often found in cubic or octahedral crystals, and 
frequently: mistaken for gold (hence called fool’s gold), 
