ANCIENT EARTHWORKS OF OHIO. 233 



been suffered to spring up, it will not be the usual mixture of 

 several species of ti'ees, but will be exclusively of one species, as 

 perhaps the locust, possessing and overshadowing the ground to 

 the exclusion of all others. 



From this he infers that after such works were executed, several 

 generations of trees must have succeeded each other before the 

 forest would have assumed the same mixed character on, and 

 within the works, as that possessed by the smTounding forests ; a 

 character of which we never find them now to be destitute, the 

 species being the same and of the same size to the very top of 

 the works, as in the suiTounding and contiguous localities. Li- 

 deed the trees on the embankment have sometimes outgrown 

 their neighbors, evidently from having an accumulated depth of 

 dug or tilled soil- to support them. This view of the subject 

 would carry back the origin of these antiquities to the Christian 

 era, and possibly beyond it. Now the point which I propose to 

 determine, is whether the waters of the gi-eat western rivers are 

 now sensibly lower than at the origin of the earthworks. These 

 antiquities evidently occupied all levels from high-water mark to 

 the tops of the highest hills ; and had there been, since theii- con- 

 struction, any general subsidence of the waters, either by diminu- 

 tion of quantity or by deepening of channels, none of them would 

 now be found to approach within the distance of such subsi- 

 dence. But the fact is that numbers of those works do now ex- 

 tend to high-water mark, and some of them aie occasionally very 

 pai-tially submerged. The general inference is then, that, for more 

 than a thousand years, at least, there has been no subsidence of 

 the streams. Whether the earthworks were ever carried much 

 below high-water mark cannot perhaps be decided, for had that 

 been the case, it is probable that repeated inundations would have 

 obliterated them. 



At Colerain, on the Great Miami, about twenty miles from its 

 mouth, there is an earthwork embankment enclosing about one 

 hundred acres. This work is mostly entire, but extending as it 

 does on a low alluvion, in a few places it has been overflowed, 

 at exti-aordinary floods, and here it becomes obscm-e or is entirely 

 obliterated. From this I infer that the channel of the Miami 

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