Some Considerations on the Mound Builders. 51 



have been the subject of much speculation. The late 

 Dr. Wilson, of Newark, told me he believed they were 

 raised gradually by successive burials ; that a layer of 

 bodies or skeletons was covered with earth ; that, after 

 some time, upon this was placed another layer of bodies 

 covered with earth ; and by such repetition the mound 

 grew. Since then, Governor Hayes, who was present 

 at the opening of the great mound at Miamisburg, told 

 me that it was marked by a stratification of earth, with 

 an appearance of vegetable mold between the layers. The 

 same appearance was noted, according to the account in 

 the American Pioneer, at the removal of the large mound 

 that formerly stood in this city. And in the exploration 

 of the Gravecreek mound, besides this stratification, the 

 soil appeared mottled, as if by the decay of perishable 

 substances inclosed in it. The same stratified appear- 

 ance is described in the appearance of similar mounds 

 in Squire and Davis' work, and in Pickett's history of 

 Alabama. In some mounds, perhaps more recent, frag- 

 ments of bones are found in the layers. This appear- 

 ance is so uniform that it is, I think, safe to agree with 

 Dr. Wilson, in ascribing the large conical mounds to a 

 gradual accretion by successive burials. 



There is another class, sometimes circular, more often 

 rectangular, having flat summits. These are called 

 truncated mounds, when the height is considerable ; 

 terraces, when the surface is large compared with the 

 height. These always have a graded ascent to the sum- 

 mit, frequently one on each side. 



These appear to have been constructed for the pur- 

 pose of having an elevated platform. This may have 



