INORGANIC COMPOSITION OF SOME AMERICAN SOILS. 21 



No. 5 sand. — Minerals other than quartz, 4.5 per cent. Potash 

 feldspars (orthoclase), 1 per cent. Muscovite, 2 per cent. Epidote 

 and augite are the predominant minerals. Chlorite, zircon, silli- 

 manite, biotite, hypers thene, magnetite, augite, plagicclases, and 

 hornblende are also present. The angular quartz grains are nearly 

 transparent, but the subangular and rounded grains inclose iron oxide. 



Silt. — Minerals other than quartz, 43 per cent. Potash feldspars 

 (orthoclase), 2 per cent. Muscovite, 5 per cent. Chlorite very 

 abundant. Biotite, sillimanite, zircon, epidote, hornblende, and 

 feldspar residues are also present. 



(16) CECIL CLAY, SOIL. 



No. 4 sand. — Minerals other than quartz, 2 per cent. No potash 

 feldspars. Muscovite, 1 per cent. Magnetite and biotite are also 

 present. 



No. 5 sand. — Minerals other than quartz, 4 per cent. Potash 

 feldspars (orthoclase), 1 per cent. Muscovite, 1 per cent. Mag- 

 netite, biotite, hornblende, and feldspar residues are also present. 



Silt. — -Minerals other than quartz, 60 per cent. Potash feldspar 

 (orthoclase), 3 per cent. Muscovite, 2 per cent. Feldspar resi- 

 dues and chlorite abundant. Epidote, zircon, magnetite, hematite, 

 biotite, and plagioclases are present. 



(17) CECIL SANDY LOAM, SOIL. 



No. 4 sand. — Minerals other than quartz, 7 per cent. Potash 

 feldspars (orthoclase), 1.5 per cent. No muscovite. Magnetite, 

 rutile, inclosed in quartz, indeterminable plagioclase, and hornblende 

 are also present. 



No. 5 sand. — Minerals other than quartz, 8.3 per cent. Potash 

 feldspars (microcline and orthoclase), 3.6 per cent. Microcline/ 

 orthoclase, and zircon are most abundant. Hornblende, muscovite, 

 magnetite, chlorite, and apatite inclusions in quartz are present. 

 Quartz grains are mostly clear, transparent, and angular to sub- 

 angular. 



Silt. — Minerals other than quartz, 30 per cent. Potash feldspars, 

 2 per cent. Muscovite, 2 per cent. Epidote, feldspar residues, 

 zircon, chlorite, and magnetite are present. 



(18) CECIL SANDY LOAM, SUBSOIL. 



No. 5 sand. — Minerals other than quartz, 12 per cent. Potash 

 feldspars (microcline and orthoclase), 3.6 per cent. Microcline, 

 orthoclase, and zircon predominate. Hornblende, magnetite, chlorite, 

 muscovite, biotite, epidote, plagioclase, and apatite inclusions in 

 quartz are aJso present. The quartz consists of an equal number of 

 clear transparent grains and those carrying inclusions or coatings 

 of iron oxide. 



