62 GEOLOGY OF ILLINOIS. 



longs, perhaps, to the Calciferous sandstone, or Lower Magiiesiau lime- 

 stone of the North-west. The next one hundred and twenty- four feet 

 almost loses its identity, but perhaps belongs to the lower Calciferous 

 sandstone and to the Potsdam sandstone. Chemical analysis of the 

 materials brought to the surface, aided by a strong magnifying glass, 

 may show these surmises to be partially untrue. We admit they are 

 little better than scientific guesses after studying the above section, and 

 examining with the naked eye and the touch specimens of the abraded 

 materials, preserved as brought up by the drill. 



We have attached some importance to the above section, because it 

 is a matter of much interest to the citizens of Stephenson county, and 

 because it afforded to the writer the only opportunity he had, in all the 

 country examined the past summer, of making even a partial examina- 

 tion of the deep, underlying formations. It also settled another ques- 

 tion then agitating the public mind in this part of the State. Before 

 this experiment, geological science had foretold that no productive oil 

 deposits would or could be found in this part of the country. It had 

 predicted this from knowledge of the underlying strata, and their ina- 

 bility to collect and preserve the oily treasures of the earth. But capi- 

 talists lacked faith in the teachings of science, and acquired in the school 

 of experience the lessons which they would nowhere else learn. The ex- 

 periment of this well had a wonderful influence in allaying the oil fever 

 in this region. 



We cannot leave this subject without rendering our acknowledgments 

 to F. E. DAKIN, Esq., of Freeport, to whom we are indebted for the fig- 

 ures in the above section, and also for small and carefully labeled spe- 

 cimens of the materials brought to the surface, during every ten feet of 

 the distance to which the well was sunk. 



We shall now proceed to describe, in detail, these outcropping geo- 

 logical formations. 



Quaternary Deposits. These deposits cover unconformably the under- 

 lying rocks to a varying depth. At some places they are five or ten feet 

 thick; at others they perhaps extend in thickness to sixty or seventy 

 feet. To say that they average twenty-five or thirty feet all over the 

 county, would, perhaps, be placing the figures satVly within the bounds 

 of truth. If all this accumulation of deposited materials could be re- 

 moved, the surface of the underlying rocks would present a very rough, 

 uneven surface. Scooped out depressions, extending through oveilyiug 

 formations and over large portions of the country, presenting, if filled 

 with water, the phenomena of broad, shallow lakes, would be seen. The 

 mounds, rising like watch towers over these prairies (resisting, on ac- 

 count of some local cause or hardness, the denuding agencies that car- 

 ried away the rest of the formation), would appear like islands in the 



