242 The Ohio Naturalist. [Vol. VIII, No. 3, 



pense of cutting to a minimum. Tracks are run alongside and 

 big steam scoops gather up the gravel and throw it into cars. In 

 addition to that used by the railroads many loads are taken away 

 in wagons. Formerly considerable sand and gravel was taken 

 from the Bluffs by boats plying on the canal; this method of 

 transportation is no longer operative, partly because of the de- 

 creased depth of this waterway. The group occupies something 

 less than a square mile of surface. But little of this acreage is 

 devoted to farming, most of it serving for pasture. There are 

 several very desirable locations for summer homes and also 

 opportunities for parking. 



Area to the East. 



The easternmost esker and the ridged relief starting on the oppo- 

 site side of the roadway at its southern end block off a portion of 

 the valley apparently belonging at one time to the Great Miami, 

 though the level of this valley is considerably higher than the 

 present flood plain of the Miami Valley. 



Conclusion and Summary. 



Eskers of Ohio have not been studied so exhaustively as those 

 of other parts of the country, particularly of New England. Lev- 

 erett, however, mentions eleven in this state, according to the 

 tabulation by Morse^^ in his article on the "Columbus Esker." 



In describing this area and in drawing inferences the writer 

 has endeavored to be exact and not dogmatic. Some slight 

 errors may have been made in data; theories in any case- are un- 

 certain. It may not be possible to work out with assurance the 

 history of the group. So many factors may have operated to- 

 gether or against each other that the result would appear to be 

 without "rhyme or reason" and too complicated for unraveling. 

 From the present day evidence, however, the following conclu- 

 sions are reached with some confidence: 



1 . These eskers conform in details to the type generally con- 

 ceded to be of sub-glacial origin. 



2. Their location was largely dependent on topography, 

 lying as they do in a position favoring active sub-glacial drainage. 



3. The heavy stratified glacial deposits other than eskers 

 also indicate an activity of drainage beneath the ice or from its 

 front. 



4. The varying texture of the boulders suggests a reworking 

 of old glacial debris by the last ice-sheet. 



5. The inexhaustible supply of gravel and sand offered, to- 

 gether with convenient location and easy access give the area 

 considerable economic value. 



23. loc. cit., p. CO. 



