BUKKAT COUNTY. 1(59 



These groves and timber belts furnish a fair supply of timber, and 

 add variety to the landscape. 



The rest of the county is prairie land, some of it level and some undula- 

 ting and rolling. The two northern tier of townships, the western and 

 south -\\estern townships, and the north parts of Hall, Princeton and 

 Selby, are such prairie lands. 



The water sheds between, these streams rise to a considerable hight 

 in places, but I had no means of ascertaining how high. The dip of 

 these water sheds and the elevation of the different parts of the county 

 above some given point, as for instance the waters of the Illinois river, 

 would aid materially in fixing the true horizon of some of the coal 

 us to be spoken of hereafter. 



Geological Formations. 



Xo county in thig part of the State presents so poor an opportunity 

 for the investigation of its geological formations. With the exception 

 of the Illinois river bluffs from Trenton towards Peru, in LaSalle county, 

 and a small ravine or two near Tiskilwa, there is hardly an outcrop of 

 a single rocky formation in the county. The Chicago, Burlington and 

 C^uincy railroad traverses the entire county diagonally from the north- 

 west to the south east corner, a distance of about forty-five miles. With 

 the exception of a few gravel beds and clay banks, its excavations pre- 

 sent no sections of interest to the geological examiner. The Bock Is- 

 land and Chicago Railroad traverses the southern part of the county 

 through its roughest portions, from the west to the east line, and the 

 same may be said of it. Green river, in this county, has no sign of an 

 outcrop in its low. swampy banks. Big Bureau. West Bureau, and their 

 tributary brooks, with but a few exceptions, cut into no rocky forma- 

 tions. When the railroads and streams, which traverse and cut a 

 county in all directions, show no natural sections of the rocks, the diffi- 

 culty of correctly describing the underlaying formations will at once be 

 seen. The following section of the Bureau county rocks and drift de- 

 posits is approximately correct. The reasons for giving it thus will 

 appear in subsequent parts of this report. 



Ideal Section of Bureau County Formation*. 

 1. Quaternary deposits, such as drift clays and gravels, loess, and alluvial clays and 



8ands 150 to 250 feet. 



Coal Measures, such as sandstones, shales, limestones, soaps tone and hard clay 250 "400 " 



3. Cincinnati group of shales I 



4. Galena limestone 



5. Trenton proper, or Blue limestone f 



Commencing with the top, I will describe these formations in the 

 order of their succession. The descriptions are made from the best ex- 

 aminations I was able so make. 



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