ANTIQUITY OF MAN. 293 



reservoirs. Another, called Clark's Work, in the 

 Scioto valley, which seems to have been a fortified 

 town, incloses an area of 127 acres, the embankments 

 ' measuring three miles in length, and containing not 

 less than three million cubic feet of earth. This area 

 incloses numerous sacrificial mounds and symmetrical 

 earthworks, in which many interesting relics and works 

 of art have been found. 



The second class the sacred inclosures, may be 

 compared for extent and arrangement with Avebury 

 or Carnak, but are in some respects even more re- 

 markable. One of these at Newark, Ohio, covers an 

 area of several miles, with its connected groups of circles, 

 octagons, squares, ellipses, and avenues on a grand scale, 

 and formed by embankments from twenty to thirty feet 

 in height. Other similar works occur in different parts 

 of Ohio ; and by accurate survey it is found, not only 

 that the circles are true, though some of them are one- 

 third of a mile in diameter, but that other figures are 

 truly square, each side being over 1,000 feet long ; and, 

 what is still more important, the dimensions of some of 

 these geometrical figures in different parts of the 

 country and seventy miles apart, are identical. Now 

 this proves the use, by the builders of these works, of 

 some standard measures of length ; while the accuracy 

 of the squares, circles, and, in a less degree, of the 

 octagonal figures, shows a considerable knowledge of 

 rudimentary geometry and some means of measuring 

 angles. The difficulty of drawing such figures on a 

 large scale is much greater than any one would imagine 

 who has not tried it ; and the accuracy of these is far 

 beyond what is necessary to satisfy the eye. We must 



