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AN AMERICAN GEOLOGICAL RAILWAY GUIDE. (MO.) 



8. Four miles southeast is Crystal City on the Mississippi River, where glass is made. The 

 Saccharoidal or St. Peter's sandstone is here forty or fifty feet thick, and over one hundred feet 

 thick in Warren County. It is very valuable for glass-making. 



9. Iron Mountain is 228 feet high, and its base covers 500 acres. 



10. Pilot Knob is a conical hill, nearly circular, 581 feet high, with a north and south diameter 

 of about one mile at its base, which covers 360 acres. 



11. Sheppard Mountain magnetic iron ore. 



12. Red shales and fusulina. 



13. Iron ores and paint clays. 



14. Salt sulphur spring. 



