170 GEOLOGICAL RECONNOISSANCE 



ORES OF IRON. 



No. 25. Yellow ochre, from the St. Francis side of Crowley's ridge, near 

 David Schultze's, between township 18 and 19, range 8, Greene county. 



A loosely aggregated, amorphous, homogeneous rock, of gold-yellow 

 color; very friable; feels gritty between the fingers; becomes brick-red on 

 ignition: 



Composition dried at 220 deg. F: 



Fine sand 71.081 



Sesquioxide of iron 23.640 



Alumina trace 



Water 5.094 



99.815 



The air-dried substance lost 1.15 per cent, of moisture at 220 deg. F. 



This ochre forms only a small deposit in the quarternary rocks of Greene 

 county, and is evidently nothing but a fine sand impregnated with hydrated 

 sesquioxide of iron, which is the coloring principle. The amount of iron 

 (15.55 per cent.) is too small to constitute this ochre an iron ore, even if 

 the deposit should prove to be very extensive; but it may be profitably 

 used as a paint, both in its natural state and calcined, since it is very soft 

 and uniform throughout, and hardly needs any washing in order to remove 

 the coarser particles. 



No. 26. Limonite, from Old Jackson, Lawrence county. 



The ore consists of contorted, more or less concentric layers of brown- 

 ish-red, steel-gray, and brownish black color; it contains amygdaloidal 

 cavities filled either with stalactitic, glossy red hematite, or with yellow 

 hydrated peroxide of iron. 



Dissolves in hydrochloric acid with evolution of chlorine. 



Composition of air-dried ore: 



Clay, sand, and silica- • • «< 15.069 



Sesquioxide of iron 58.278 



Sesquioxide of manganese 13.843 



Alumina trace 



Oxide of cobalt trace 



Carbonate of magnesia 0.664 



