G E N E R A L O B S E R V A T I O N S . 5 



four hundred acres.* The magnitude of the area enclosed is not, however, always 

 a correct index of the amount of labor expended in the erection of these works. A 

 fortified hill in Highland county, Ohio, has one mile and five-eighths of heavy 

 embankment ; yet it encloses an area of only about forty acres. A similar work 

 on the Little Miami river, in Warren county, Ohio, has upwards of four miles of 

 embankment, yet encloses little more than one hundred acres. The group of works 

 at the mouth of the Scioto river has an aggregate of at least twenty miles of em- 

 bankment ; yet the entire amount of land embraced within the walls does not 

 probably much exceed two hundred acres. 



The mounds are of all dimensions, from those of but a few feet in height and a 

 few yards in diameter, to those which, like the celebrated structure at the mouth 

 of Grave Creek in Virginia, rise to the height of seventy feet, and measure one 

 thousand feet in circumference at the base. The gTeat mound in the vicinity of 

 Miamisburgh, Montgomery county, Ohio, is sixty-eight feet in perpendicular 

 height, and eight hundred and fifty-two in circumference at the base, containing 

 311,353 cubic feet. 



Flo. i. GREAT MOUND AT MIAMISBURGH, OHIO.t 



The truncated pyramid at Cahokia, Illinois, has an altitude of ninety feet, and is 

 upwards of two thousand feet in circumference at the base. It has a level summit 

 of several acres area. The great mound at Selserstown, Mississippi, is computed 

 to cover six acres of ground. Mounds of these extraordinary dimensions are most 

 common at the south, though there are some of great size at the north. The usual 

 dimensions are, however, considerably less than in the examples here given. The 

 greater number range from six to thirty feet in perpendicular height, by forty to 

 one hundred feet diameter at the base.:}: 



* Lewis and Clarke describe one on the Missouri river which they estimated to contain not far from 

 six hundred acres. — Travels, p. 4Y. 



j- From a sketch by Henry Howe, Esq. 



J " We have seen mounds which would require the labor of a thousand men employed upon our canals, 

 with all their mechanical aids, and the improved implements of their labor, for months. We have more 

 than once hesitated, in view of one of these prodigious mounds, whether it were not really a natural hill. 

 But they are uniformly so placed, in reference to the adjacent cnunti'v, and their conformation is so unique 

 and similar, that no eye hesitates long in referring them to the class of artificial erections." — Flinl's 

 Geograpliij. p. 131, 



