388 index. 



PAGE. 



Devonian System 184 



Drainage Systems of the State 38 



Drift 82 



altered 101 



boulders of 85 



coal in 97 



copper in « 96 



distribution of 85 



evidences of glacial origin of 92 



evidences of northern origin of 90 



fossils in 98 



gold in 97 



gravel of 84 



lead ore in 96 



moraines (?) of 98 



origin of . 89 



sand of , 84 



thickness of •. 88 



wood in 97 



Elevation of principal points in the State, table of 30 



Forest trees, growth of in prairie soil 129 



Forest trees of Iowa 134 



Fremont county 353 



Galena limestone 176 



Geological principles, popular explanation of 12 



Glacial currents, traces of 92 



Glacial scratches 92 



Glaciers, passing away of. 99 



Hamilton limestone and shales 184 



Historical account of geological survey of Iowa 7 



Ice cave of Decorah 80 



Introduction 2 



Irish, C. "W., Railroad elevations 31 



Keokuk limestone 210 



fossils of 213 



Kinderhook beds 191 



exposures of, near Legrand 197 



in Pocahontas county 199 



thickness of, at Burlington 192 



Lakes 70 



Laws authorizing geological survey 8, 10, 11 



