58 GENERAL INDEX. 



Devonian system 1,119-152; Il.xi; 111,393; YIII.63 



Dikes, how formed 1, 23 



Disturbed strata '. 1,5-9,458; IV.2; VII,39,41 



Driftless region of the Northwestern counties 1,28,160 



Drift See Quaternary system. 



Epsomites 1,492; 111,43 



Erosion in Illinois 1,9; IV.237; VIII.3,11, 28,34 



Faults 1,458; IV.2 



Fish beds 11,11-16; IV.345; VI, 247; VII.59 



Flora of Illinois, contributions to 1,280,342,375,406; IV.109; V.158; VI.63 



Fluor spar Ill, 19 



Fossils, use and value of 1,17 



Fusulina limestone VII, 27 



Gas, distilled from coal by different methods 1,266 



" .natural IV.206; VI.192; VIII,13,58.61 



Galena 1,141-149,155-207; 111,301; V.17-21 



Galena beds See Trenton. 



Gait limestone 1,130 



Gash veins 1, 23 



GeoJes of the Keokuk group; by G. J. Brush 1.92 



Geological survey of Illinois, history of I.ix-xvi; Il.vi.vii; VI.v; VIII, Appendix, 12 



systems, order of 1,21; Il.viii 



Geology, general principles of 1. 10; Il.i-v 



Glacial theory V.5; VIII.19 



Glencoe marble V.282 



Glossary of scientific terms 1,497-504 



Gold , 1,35; 111,18; 1V.263 



Goniatite limestone 1,109 



Grindstone grit VII, 37 



Hamilton group 1,120: II.xv; 111,22,419 



Hard pan 1,25 



Helderberg, Lower and Upper II, viii 



Hudson river group. 1,137; II,xvi-xix 



Huronian system 1,22, 163 



Ichthyic beds See Fish beds. 



Illinois, physical features of 1, 2-10 



Indian remains 1,455,495; IV.222; V, 93, 102,165; VI, 30, 146,216, 224 



Iowa Cretaceous strata in VIII, 6 



" Marshall county strata and fossils VIII, 157 



Iron ores 1, 61, 256 ; V, 263 



Kaskaskia limestone 1, 42 



Keokuk group 1,89-102; III.508; VII. 16 



Kinderhook group 1,43,108-118; II, ix; 111,450; VIII.158 



Lake Michigan, ancient outlet of IV.191,237; VIII, 11,14. 28, 33, 36,39 



Lakes in Illinois IV.128 ; VI, 173 



Lake tunnel, peculiar features of 111,243 



Land slides IV, 127 



Laurentian system 1, 22, 112 



Lead mines in Hardin Co., report by Dr. J. G. NORWOOD 1,366-373 



letter from H. M. THOMPSON Ill, 17-16 



Lead region, geology of, report by Prof. J. D. WHITNEY 1,153-207 



Lignite 1,45,74 



Lime, material for 1,324; VII, 40 



Limestone, Archimedes II, 13 



Athens (marble) 1,133 



