FULTON COUNTY. 91 



in the region about Fairview, there are some quite flat prairies that require 

 draining in wet seasons. The soil on the prairies is a dark brown or black 

 mould, varying from one to three feet in depth, with a sub-soil of brown clay 

 loam. 



The bottom lands, on the western bank of the Illinois river in this county, 

 are from .one to four miles in width, and are mostly covered with timber, 

 though there is some bottom prairie near the mouth of Spoon river. A good 

 deal of this bottom land is too low and marshy for cultivation, but where it is 

 sufficiently elevated, the soil is a rich sandy loam, and very productive. The 

 bluffs generally range from one hundred and twenty-five to one hundred and fifty 

 feet in height, and are usually cut into sharp ridges by the valleys of the small 

 streams that drain the adjacent region. The lower part of these blufls, to the 

 height of seventy-five to one hundred feet, consist of the stratified rocks of the 

 Coal Measures into which the original valley was excavated, ana* their elevation 

 has been subsequently increased by the accumulation of Drift clays and lacus- 

 trine deposits upon them. The valley of Spoon river seldom exceeds a mile in 

 width, and is excavated into the Lower G&rboniferous limestone on that part of 

 its course, extending from Seaville to Bernadotte. The depth^of this valley is 

 about the same as that of the Illinois river, but the lower rocks are reached 

 here, in consequence of the easterly dip of the strata, which brings the lime- 

 stones nearer to the surface in the western portion of the county. 



Surface Geology. 



The surface deposits of Fulton county consist of Drift clays and gravel, with 

 the subsequent lacustrine and alluvial accumulations. The Drift proper, ranges 

 in thickness from thirty to sixty feet, or more, and is usually composed of 

 brown and bluish colored clays with gravel, and boulders of metamorphic and 

 igneous rocks, varying in size from a pebble to masses of several tons weight. 

 Usually, the brown clays constitute the upper portion of the deposit, and the 

 blue clays the lower. In the vicinity of Utica, a bed of ferruginous conglom- 

 erate, about two feet in thickness, underlies the Drift clays, and similar beds, 

 in local outliers, have been met with in the same position, at several localities 

 in the State. This conglomerate exactly resembles the bed at Metropolis, in 

 Massac county, on the Ohio river, which has been usually referred to the Ter- 

 tiary period, and may be of the same age. 



On the west side of Big creek bridge, near Canton, in grading the track for 

 the T. P. & W. railroad, a band of black mould or soil, containing leaves and 

 fragments of wood, was found below the Drift clays, which is, no doubt, a part 

 of the ancient soil covering the surface anterior to the Drift epoch. A similar 

 bed has been found in sinking shafts and wells in various parts of the State, 



