MARSHALL AND PUTNAM COUNTIES. 213 



well adapted to agriculture as the more level portions of the State, will 

 produce fruits iu perfection, and the cereals grown upon them have a 

 plumper berry and more weight than those grown upon the flat prai- 

 ries. 



Leaving these intermediate tracts of rough barrens, the rest of the 

 county, both on its eastern and western sides, settles off into the usual 

 level Illinois prairie laud. On the east this strip of prairie is from six 

 to twelve miles wide. It is generally quite flat, with a few gently swell- 

 ing elevations. It is almost devoid of timber, of stone, of coal, and of 

 large stieams of water. The soil is black and fat, but in wet seasons 

 much of it is a b'ttle too flat. Along the western part of the county the 

 prairie is more rolling, dryer, and with a lighter, warmer soil. 



Das. Except the Illinois river, there are no streams of any size 

 in the county. All Forks " is a considerable sized brook ; the rest of 

 the county, and especially the more level prairies, have many small 

 brooks and rivulets, for the most part without steep banks or hills. 

 They are essentially surface streams, dry in dry seasons, and draining 

 off the surface water in wet ones. 



Geology . 



Quaternary System. There is nothing of special interest in the geo- 

 logy of this county. Outcrops are few and far between. The variety 

 of formations is very limited. The surface geology is made up of the 

 usual Quaternary deposits. The soil and sub-soil of the prairies, the 

 few narrow creek bottoms, and the usual Illinois river bottom, are well- 

 marked alluvial deposits. Of these nothing need be said, except almost 

 to reiterate the statements about the same deposits of Marshall county. 

 Along the Illinois river there is the same low bottom, slightly contracted 

 in width. The present flood plain of the river is composed of the same 

 fine, black, soft-grained mud and silt, very fat and productive when 

 dry enough for cultivation ; the same banks and beds of variously 

 colored sand of different degrees of fineness, according to the condi- 

 tions of the waters which assorted, arranged, and deposited it ; the same 

 system of sloughs, willow growths, and meadows of rushes, and water 

 grasses ; and the same oozy pools of green scum, pestilent-breeding beds 

 of agues and intermittent fev- 



Along the Hennepin prairie, and in a few other localities, there are 

 considerable strips and stretches of river terrace land, the ancient flood 

 plain of the river, when its waters ran many feet higher than they do 

 now. Some very tine farms, in the vicinity of Hennepin, are made upon 

 this older alluvial deposit. Few traces of the loess clays and marls 



