Plate 38 



TILL PLAINS 



LAKE PLAINS 



o 



TwTThc 



r 



I ASHI.ANO 



"""" GLACIATED 



ALLEGHENY """"' 

 PLATEAU 



COLUVBI*"* 



MONTGOMERY ' 



CHAUPAION 



-JrRANKLlN 



PfCKAWAy 



J COSHOCTON 



^^^ 





5^^ 



kJO lOUtOHSET 



I 



UNGLACIATED 



ALLEGHENY 



PLATEAU 



FLUSHING 

 ESCARPMENT 



a 



BLUE GRASS 

 REGION 



Map 77. The Physiographic Areas of Ohio (after Peattie, but amended to confoim with Maps 1 

 and 2 in the "Geology of Water in Ohio," by Stout, Ver Steeg, and Lamb, 1943). The Lake Plains are 

 characteristically level and are bounded by old beach lines marking the maximum extent of Lake Maumee 

 in postglacial times. Low rolling hills cover much of the Till Plains area, which is terminated on the east 

 by the eastern limit of the Upper Devonian shales. The Allegheny Plateau is more deeply dissected, 

 especially in the unglaciated portion, and the bedrock is chieflj^ sandstone, shale, and conglomerate. Tht 

 western half of the state rests upon the limestone of the Cincinn-'.ti geanticline. The Blue Grass Region 

 is the only extensive limestone country in the state that escaped glaciation. Tlie Glacial Boundary and the 

 Flushing Escarpment are indicated. 



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