CROP REGIONS OP OHIO 



46 



There are some interesting features of the drainage of the 

 state which should be emphasized because of their bearing upon 

 the biota. From a biological point of view all of the valleys are 

 regarded as special means of ingress of animals and plants. It is 



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• "^^~_^ Toledo 



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calo 



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Fig. 8. Map of Ohio showing glacial moraines and the limits of the drift left by the ice at 

 its several stages. The arrows indicate the direction of the ice movement. After Leverett, in 

 Geologic Atlas, Columbus folio 197. 



not surprising then that many plants of the northeastern evergreen 

 forest have found their way into Eastern Ohio from the lake and 

 southward along the valleys which drain into the St. Lawrence 

 basin. Furthermore, a number of strictly southern species have 

 made their way into Central Ohio by progressing northward along 

 the valleys which are tributary to the Ohio. The state which lies 

 within the deciduous forest then, serves as a meeting ground for 

 both plants and animals of the northern and southern evergreen 



