426 TROPICAL NATURE 



ing 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 hav^e been found. 



The second class the sacred inclosures may be compared 

 for extent and arrangement with Avebury or Karnak, but 

 are in some respects even more remarkable. 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 1000 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, therefore, 

 impute to the builders the wish to make these figures as 

 accurate as possible, and this wish is a greater proof of 

 habitual skill and intellectual advancement than even the 

 ability to draw such figures. If, then, we take into account 

 this ability and this love of geometric truth, and further 

 consider the dense population and civil organisation implied 

 by the construction of such extensive systematic works, we 

 must allow that these ancient people had reached the earlier 

 stages of a civilisation of which no traces existed among the 

 savage tribes who alone occupied the country when first 

 visited by Europeans. 



The animal mounds are of comparatively less importance 

 for our present purpose, as they imply a somewhat lower 

 grade of advancement; but the sepulchral and sacrificial 



