4IO 



The Ohio Naturalist. 



[Vol. XV, No. 3, 



The region of Sandusky Bay and the islands is peculiar in 

 many respects, being a meeting place of many species. The 

 Sandusky area is apparently a biological island containing num- 

 erous species heretofore not discovered in any other part of the 

 state. The Sugar Grove area also contains a number of unusual 

 isolated species but is not so sharply defined as the Sandusky 

 Bay area. 



Important Geographic Boundaries in Ohio. 



There is a general transition belt between the eastern and 

 western portions of the state, situated between the eastern limit 

 of the Ohio Shale on the one hand and the glacial boundary and 

 the limit of the higher hill country on the other. See Map I. 

 The lake shore may also be considered as a more or less distinct 

 l)lant area, but such details arc not considered in this paper. 



