262 GEOLOGY OF ILLINOIS. 



in Schuyler and Fulton comities, yet they have not only furnished an 

 abundant supply of coal for home consumption, but for many years 

 have furnished many thousands of tons annually for shipment south 

 and west to the adjoining counties. The shipment from Colchester 

 alone for the years 18G6 arid '67 was about 500,000 tons per annum, and 

 the product of the mines has been constantly on the increase* The coal 

 obtained here is of excellent quality if taken out at some distance from 

 the outcrop, where it has not been exposed to atmospheric influences. 

 The coal is tolerably hard, bright, and comparatively free from pyrite, 

 and breaks freely into cubic blocks when mined. An analysis of this 

 coal by Mr. HENRY PRATTEN, as reported in Dr. NORWOOD'S "Analy- 

 ses of Illinois Coals," gave the following result : 



Specific gravity 1-5290 



Loss in coking 41.2 



Total weight of coke 58 8 



100 



ANALYSIS. 



Moisture 5.4 



Volatile matters 35 8 



Carbon in coke 1 56 . 6 



Ashes (light-gray) 2.0 



100.0 

 Carbon in coal 60 10 



This analysis shows this to be one of the best coals in the State, and 

 its freedom from pyrite has always made it a favorite coal with the 

 blacksmiths of this and the adjoining counties. The coal from the 

 lower seam is usually harder than that from the Colchester seam, and 

 less uniform in quality. Its thickness is also more variable, and fre- 

 quently the coal is wanting altogether, and its place occupied by bitu- 

 minous shales. Nevertheless, it sometimes attains a thickness of three 

 feet, as at Seaville, in Fulton county, and the coal obtained there is of 

 a fair quality. It is quite probable that this seam may be found in some 

 of the eastern townships in this county, as thick as it is at Seaville, 

 and if so, it might be worked to advantage, as its depth below the sur- 

 face would probably nowhere exceed two hundred feet. 



No. 3, if found at all in this county, would be met with in the upper- 

 most layers of the bed rock, and immediately underneath the boulder 

 clays, except at a few points, where it might be overlaid by a few feet 

 of sandstone or sandy shale. It is less persistent in its development, 

 however, than either of those below it, but its proper horizon may be 

 readily recognized by the dark-blue limestone and bituminous shales 

 that are nearly always present, even when there is no development of 

 the coal itself. 



A boring carried down to the depth of two hundred feet would probably 

 pass entirely thiough the Coal Measures in any portion of the county, 



