614 THE ILLINOIS GLACIAL LOBE. 



WHITESIDE COUNTY. 

 GENERAL STATEMENT. 



Whiteside County borders the Mississippi River in the third tier of 

 counties from the north line of the State and has an area of 700 square 

 miles, with Morrison as its county seat. Rock River leads through the 

 county from the eastern border to the southwest corner and receives the 

 drainage of the greater part of the county, only a narrow belt on the north- 

 west being directly tributary to the Mississippi. The southern half of the 

 county is a lowland tract standing but little above the level of Rock River, 

 its general elevation being about 650 feet above tide. The northern and 

 western portions have an altitude corresponding with that of the uplands 

 in Carroll and Ogle counties, the altitude of a considerable part being 

 above 800 feet and in places reaching nearly 900 feet. Two narrow low- 

 land tracts, resembling river valleys, connect the Mississippi River with 

 the lowland bordering Rock River, one of which, on the southwest border 

 of the county, is known as Meredosia Slough, and one, leading from near 

 Fulton to Fenton, as Cattail Slough (see PI. XVIII). These sloughs stand 

 so little above the level of the Mississippi and Rock rivers that they are 

 occupied in flood stages of either stream, and the direction of flow depends 

 upon the stream which chances to have the higher stage. 



On the uplands the drift is of variable thickness, but is generally 

 thinner in the northern and northeastern portions than in the western por- 

 tion of the county. The general thickness, however, seldom falls below 

 50 feet even on ridges. In the western portion, from near Fulton south- 

 ward past Garden Plain to Erie, there appears to be an average thickness 

 of fully 150 feet. Were this drift removed, the elevation would differ but 

 little from that of the lowland tracts bordering Rock River, for rock is 

 often found at slight depth beneath these lowlands except in the southeast 

 portion of the county. In the uplands of the northern portion of the 

 county some wells are sunk to considerable depth in the rock. In the west- 

 ern portion they usually obtain water in the drift or at slight depth in the 

 rock. On the lowlands north of Rock River the wells are g-enerally shal- 

 low and often enter the rock a few feet. In the southeastern part of the 

 county much of the land has not been brought under cultivation, the sur- 





