PAPERS ON GEOGRAPHY AND GEOLOGY 381 



in the west including the east half of Jersey, most of 

 Greene, Scott, Brown, and Schuyler counties, with ad- 

 joining parts of Cass, Morgan, Pike, and Adams, most 

 of McDonough, with adjoining parts of Fulton, Knox, 

 and Hancock counties. 



(2) The second grade considered "possible" should 

 include the rest of the State not included in the two 

 following grades. 



(3) The area considered "improbable" includes the 

 central structural basin running south on the west of 

 the La Salle anticlinal uplift, including small parts of La- 

 Salle, Marshall, Woodford, and Livingston, the central 

 north and south portions of McLean, most of DeWitt, 

 east half of Macon, Piatt, Moultrie, Shelby, west portions 

 of Douglas, Coles, and Cumberland, Jasper, Effingham, 

 east portion of Fayette, all but a western part of Marion, 

 Clay, Richland, west part of Lawrence, Edwards, Wayne, 

 most of Jefferson, Hamilton, and White counties, with 

 adjoining portions of Saline and Gallatin counties. 



Another area of similar status is the trough or syn- 

 cline between the two folds of the LaSalle uplift flanking 

 the areas along the axes including parts of Ford, Cham- 

 paign, Douglas, and Coles counties. Also the flank on 

 the east of the uplift including parts of Iroquois, Ver- 

 milion, Edgar, Clark, and Crawford counties should be 

 included. 



In the general area in the northern part of the State 

 where, due to the northward regional rise of the strata 

 particularly along the axis of the pitching LaSalle up 

 lift, most of the formations containing oil horizons are 

 not present. The so-called Trenton or Galena limestone 

 and the underlying St. Peter sandstone outcrop here. 

 Oil has never to our knowledge been obtained in com- 

 mercial quantities from the St. Peter or underlying older 

 formations. These contain few shales and apparently 

 have not the requisite source or favorable conditions gov- 

 erning accumulation of oil. The areas on the flanks of 

 the anticline where no adequate capping exists for the 

 outcropping Galena limestone should be included also 

 in the improbable area. This includes most of Win- 

 nebago, Boone, with adjoining portions of McHenry 



