WHITESIDE COUNTY. 145 



its southern boundary, like some Niagara, pouring out the overflow of 

 the great lakes of the North. This barrier over which the water rushed, 

 -M! the river, like a great dam, where the "Devil's Bake-oven^ is now 

 pointed out to the traveler. As this was worn down and the bed of the 

 Missis>ippi lowered, the water assumed more and more the form of a 

 river, draining the great basin thus exposed. The action of the low run- 

 ning waves and other aqueous agencies threw up and arranged in part 

 the bluff* around its shores, while the great basin was full of compara- 

 tively currentless water. This deposit is the loess. It is composed of 

 light colored, finely comminuted clays, white and yellow sands and 

 sandy marls, all generally partially stratified, and containing lacustriue 

 and fluviatile shells and other fossils. The loess bluffs are generally 

 bald knobs, covered with short tufts of grass. A good example of the 

 loess may be seen where the North-western railroad strikes the bluffs 

 of Fulton city. The bluffs here are made up nearly altogether of 

 the loess. South of this, along the Cat-tail, the bluffs are in part capped 

 by the same deposit : but in going north they soon rise into the rocky 

 walls and high mural escarpments of the Niagara limestone. The low 

 hill north and west of Morrison is partly composed of loess clays. Bock 

 river and the smaller interior streams did not present favorable condi- 

 tions for this deposit to take place, and we seldom find it away from the 

 bluffs of the Mississippi river. 



Drift. There is a marked distinction between the drift in this and 

 counties farther east. The coarse gravel beds of its upper division are 

 almost entirely wanting. The recent gravels of Kock river were the 

 only real gravel deposits I observed. The usual blue colored and yellow 

 plastic clays of the lower drift cover the underlying rocks in many places 

 to a considerable thickness. At one locality a well was sunk twelve or 

 fifteen feet through yellow unctions clay ; then blue clay was struck, 

 and in about fifteen feet more a great quantity of sticks and wood, ap- 

 parently cedar and pine, was found. The water in the well, of course, 

 had a brackish taste. This woody deposit was about the base of the 

 true drift. Occasional boulders are found in the ravines, but they are 

 no where abundant. Over the northern parts of the county, and espe- 

 cially that portion underlaid by the Galena limestone, the reddish clays 

 or hard pan of the lead region exists to a considerable depth. These 

 drift clays however, as developed in this county, have in them nothing of 

 peculiar or marked interest, except that they bear evidences of peaceful 

 forces rather than that tremendous power which strewed the boulders 

 and piled up the gravel beds in many places in the neighboring counties. 

 Whether the floating iceberg, or the slow crawling glacier, or the strong 

 water currents, or all these combined, transported the coarser materials 

 of the drift, the force of the powerful agents were much modified in 



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