ILLINOIS STATE GEOLOGICAL SURVEY. 



MONOGRAPH No. 1. PLATE VIII. 



8 



9 



10 



12 



13 



14 



15 



11 



16 



25 



18 



19 



20 



17 



21 22 23 24 3 31 33 



26 27 28 29 32 34 



J 



35 



* 



36 



37 



J 



38 



r 



39 



r 



40 



42 



43 44 45 46 



47 



Jl J J 



5O 51 52 53 



48 49 



54 55 56 57 



73 



