INORGANIC COMPOSITION OF SOME AMERICAN SOILS. 17 
Silt. — Minerals other than quartz, 40 per cent; potash feldspars, 
7 per cent; muscovite, 0.5 per cent. Epidote is present in fairly large 
quantities. Hornblende, rutile, zircon, chlorite, magnetite, and 
sponge spicules are also present. 
(2) NORFOLK SANDY LOAM, SUBSOIL. 
No. 4 sand. — No potash feldspars. Practically pure quartz with 
rutile and apatite inclusions. Andesite present. 
No. 5 sand. — Minerals other than quartz, 4.7 per cent. Quartz 
grains very clear and bright, mostly well rounded, with a few &ub- 
angular and angular grains. Tourmaline, rutile, zircon, chlorite, 
magnetite, cyanite, hypersthene, weathered feldspars, and apatite 
inclusions in quartz are present. 
Silt. — Minerals other than quartz, 60 per cent. Potash feldspars 
(orthoclase), 1 per cent, characterized by a large amount of highly 
kaolinized feldspars and the presence of sponge spicules. Epidote, 
chlorite, rutile, orthoclase, and zircons are also present. 
(3) DECATUR CLAY LOAM, SOIL. 
No. 4 sand. — Minerals other than quartz, 4 per cent. Potash 
feldspars, negligible. No muscovite. Magnetite, hematite, rutile 
inclosed in quartz, orthoclase, and epidote are present. 
No. 5 sand. — Minerals other than quartz, 4.2 per cent. Potash 
feldspars (orthoclase), less than 0.5 per cent. No muscovite. The 
feldspars are much altered and few in number. Rutile, zircon, tour- 
maline, magnetite, and epidote are also present. Characterized by 
quartz crystals inclosing iron oxide. 
Silt. — Minerals other than quartz, 39 per cent. Potash feldspars, 
6 per cent. The feldspars are much altered. Epidote and chlorite 
are the predominating minerals. Tourmaline, rutile, and zircon are 
also present. 
(4) DECATUR CLAY LOAM, SUBSOIL. 
No. 4 sand. — No potash feldspars or muscovite found. The quartz 
is very impure. Magnetite, hematite, and rutile inclosed in quartz 
are present. 
No. 5 sand. — Minerals other than quartz, 4 per cent. Potash 
feldspars less than 0.5 per cent. The quartz grains are well rounded 
and subangular. Tourmaline, zircon, rutile, magnetite, and calcite 
inclosed in quartz are also present. Characterized by quartz crystals. 
Silt. — Minerals other than quartz, 37.5 per cent. Potash feld- 
spars, 9 per cent. Zircon, epidote, tourmaline, magnetite, muscovite, 
chlorite, and sponge spicules are also present. 
