172 GEOLOGICAL RECONNOISSANCE 



brown and blackish-brown color, with occasional yellow spots; fracture 

 dull, dark reddish-brown; emits argillaceous odor when breathed upon; 

 adheres slightly to the tongue. 



Composition of air-dried ore: 



Silica and clay 3.090 



Sesquioxide of iron 83.920 



Sesquioxide of manganese trace 



Alumina 1.710 



Lime trace 



Water • 11.580 



100.300 

 83.920 parts of sesquioxide of iron contain 59.74 parts of metallic iron. 



No. 30. Limonite, four miles south-west of Imboden's ferry, Randolph 

 county. 



Exterior crust dirty reddish-yellow, earthy; in the interior dark bluish- 

 brown, consisting of indistinctly concentric, contorted layers; loosely 

 aggregated; rather soft; evolves strong argillaceous color when breathed 

 upon; strongly adhering to the tongue; powder of a dirty brownish olive- 

 green color, becoming dark reddish-brown on ignition. 

 Composition of air-dried ore: 



Insoluble silicates 7.740 



Sesquioxide of iron 66.808 



Sesquioxide of manganese 11.472 



Alumina 1 295 



Lime trace 



Phosphoric acid trace 



Water 13.337 



100.652 

 66.808 parts of sesquioxide of iron contain 46.76 parts of metallic iron. 



No. 31. Limonite, four miles west of Salem, Fulton county. 

 Massive; very compact; on surface brownish-yellow; on fracture 

 brownish-red, with steel-gray spots and stripes; fracture subconchoidal: 

 evolves argillaceous odor when breathed upon; adheres to the tongue. 

 Composition of air-dried ore: 



Insoluble silicates and sand 20.722 



Sesquioxide of iron 68.543 



Sesquioxide of manganese 1.221 



