i86 



TRANS. ST. LOUIS ACAD. SCIENCE. 



Mountain and Iron Mountain ; lenticular veins, Iron Mountain 

 and Hogan Mountain ; as segregations and impregnations, in the 

 Porphyry matrix throughout what is known as the iron region. 



Manganiferous iron-ore was discovered at several points, but 

 only in one place to my knowledge does it occur in sufficient 

 quantities for mining purposes ; here it has a thickness of four- 

 teen feet, and yields from lo to 12 percent, of manganese. I 

 would here remark that this ore is one of the most impoi'tant of 

 the iron ores, yielding one of the finest products for the manufac- 

 ture of steel. 



On the table you will find specimens of iron-ore with the analy- 

 sis of each attached ; the iron-ores from other localities have also 

 been analyzed, but I did not feel at liberty to make known their 

 results until after the publication of this year's Report on the 

 Geology of Missouri. After the said Report appears, I will at- 

 tach to each their respective analysis. 



The following analyses are made from specimens from Pilot 

 Knob, Cedar Mountain, Shepherd Mountain, Buford Mountain, 

 and Iron Mountain. From Pilot Knob there are two varieties, 

 one from above the seam, the other below the seam of clay slate. 

 The lean ore contains a large per cent, of porphyry ; below the 

 seam is the richer ore, from w^hich most of the iron is derived. 



The Buford Mountain ore is rich in manganese, and will fur- 

 nish a fine Spiegeleisen, from which no doubt, later, a fine qual- 

 ity of steel will be manufactured. 



PILOT KNOB. 



Insoluble silicious matter, 

 Peroxide of iron, 

 Protoxide of iron, 

 Alumina, . . . 



Lime, - - - - 

 Magnesia, - - - 

 Manganese, 



Sulphur, ... 



Phosphoric acid, - 



Metallic iron, 

 Phosphorus, 



Specific gravity, 



Above the Seam. 



