Malott: The "American Bottoms'' Region 



7 



feet above sea level; so that its elevation is about 100 feet 

 greater than the adjacent valleys. A brief inspection of the 

 topographic map reveals at once the presence of two west- 

 wardly extending, gently undulating ridges, formed by the 

 bifurcation of a single broad ridge near Cincinnati. From 

 these two ridges numerous spurs extend out to the north and 

 south. The deep valleys of Beech and Cliffy creeks lie on 

 the north and south respectively, while the broad elevated 

 valley of the ''American Bottoms", with its peculiar drain- 

 age, lies between the two ridges. To the southwest, north of 

 Koleen, is a broad ridge between Plummers and Cliffy creeks. 

 This ridge is terminated rather abruptly by the narrow valley 

 of Cliffy Creek, which cuts it in two, leaving a subdued rem- 

 nant on the west side. It is in this region that the most 

 prominent cliffs appear. Sheer descents of 50 to 75 feet are 

 found, and these are responsible for the name Cliffy Creek. 



Further discussion of the drainage and topography will 

 be given in the section on the detailed description and inter- 

 pretation of the physiographic features of the region. 



THE GEOLOGY OF THE "AMERICAN BOTTOMS" 

 REGION AND THE TOPOGRAPHIC AND 

 PHYSIOGRAPHIC INFLUENCES OF 

 THE LITHOLOGIC UNITS 



Under this head it is the intention to emphasize the stratig- 

 raphy of the region with special reference to the lithologic 

 succession. Formation names will be used mainly for the 

 identification of the horizons under discussion, and for the 

 purpose of calling attention to such strata as are clearly re- 

 sponsible for topographic and physiographic forms. Since the 

 position of certain strata at critical levels is important, the 

 general structural conditions are also discussed. In this 

 respect it may be said that the general dip to the west- 

 southwest at the rate of approximately 30 feet per mile car- 

 ries the higher strata of the eastern part of the area to lower 

 and lower positions to the west and south. As in the dis- 

 cussion of drainage and topography, attention was directed 

 to the topographic map, so here attention is called to the 

 geologic map, and especially to the areal distribution of the 

 strata and to the, stratigraphic column at the right of the 

 geologic map. This column shows by the usual conventional 



