90 



ILLINOIS ACADEMY OF SCIENCE. 



Litt •( Conntics 



No. 



1 Jo Daviess. 



2 Stephenson. 



3 Winnebago. 



4 Boone. 



5 McHenry. 



6 Lalte. 



7 Cook. 



8 Du Page. 



9 Kane. 



10 Deltalb. 



11 Ogle. 



12 Lee. 



13 Carroll. 



14 Whiteside. 



15 Rock Island 



16 Mercer. 



17 Henry. 



18 Bureau. 



19 Putnam. 



No. 



20 Lasalle. 



21 Kendall. 



22 Grundy. 



23 Will. 



24 Kankakee. 



25 Iroquois. 



26 Ford. 



27 Livingston. 



28 Marshall. 



29 Woodford. 



30 Stark. 



31 Peoria. 



32 Knox. 

 3 3 Warren. 



34 Henderson. 



35 Hancock. 



36 McDonough. 



37 Fulton. 



38 Mason. 



39 Tazewell. 



40 McLean. 



41 Vermillion. 



Plate I. Maps of Northern Illinois showing locations of towns and 

 drill holes between Rock Island and Joliet. 



