ECONOMICAL GEOLOGY. 25 



CHAPTER II. 



ECONOMICAL GEOLOGY. 



COAL. 



Since the publication of Vol. VII, of these reports, numerous 

 experiments have been made for the development of our coal 

 resources, the great majority of which have proved successful. 

 Among the most notable failures were those made at Tuscola 

 in Douglas, and Sidney in Champaign counti< - 



Tuscola is situated some forty miles or more within the east- 

 ern border of the coal field, and also within the region supposed 

 to be underlaid by the upper coal measures, but, a boring made 

 there with the diamond drill to the depth of 792 feet, failed to 

 reveal the presence of coal, or any clearly defined strata be- 

 longing to the coal measures. 



The drift deposits were found to be 186 feet thick at the point 

 where the boring was made, and if beds belonging to the coal 

 measures were originally deposited there, they were removed by 

 erosion at the commencement of the drift period, and the first 

 layers of bed-rock encountered by the drill appeared to be of 

 Lower Carboniferous age. At the depth of 645 feet a white 

 crystalline limestone containing Favosites was encountered, 

 which undoubtedly belongs to the Devonian or Upper Silurian 

 formations. 



The oblique fracture of the core taken from this boring, showed 

 that the limestones passed through, dip at an angle of about 

 20, which would give an exaggerated thickness to the beds as 

 reported, and shows that this boring is on, or very near the 

 center of the great anticlinal axis, which crosses northern Illi- 

 nois diagonally through the counties of Ogle and LaSalle, but 

 o 



