# Precise Measurements in Ancient Earthworks

Surprisingly, the dimensions of the geometric enclosures appear to have been precisely measured. The dimensional relationships between shapes within an earthwork complex sometimes show mathematical relationships. Even more amazing, shapes in *different* earthwork complexes appear to share common dimensions. Consider the 1848 maps drawn by Ephraim Squier and Edwin Davis below.

In this case, a 20 acre circle with an approximately 1,050 foot diameter appears in five separate earthwork complexes, Seal, High Bank, and Hopeton Earthworks (pictured above), as well as the Newark and Circleville Earthworks, even though these complexes were many miles away from each other. This astounding fact is compelling evidence that the Hopewell people had some sort of common unit of measure. But this is just one example of such evidence.

In the below complexes, not only do the complexes show a remarkable common design: little circle, big circle and square, but the dimensions of the shapes show surprising similarity *between* the five complexes. For instance, when Squier and Davis measured them in the 1840’s, they found that all the squares were the same size, 1,080 feet to a side, enclosing 27 acres.

What’s more, the relationships between shapes within an earthwork provide evidence that the Hopewell architects understood mathematical relationships between circles and squares and that these relationships were important to them. In the Seip, Works East and Frankfort Earthworks above, the diameter of the large circle equals the diagonal of the square, such that the square nests right into the large circle.

As seen in the map below, the Newark Earthworks contain a square with the same perimeter (red) as the circumference (red) of the Great Circle. Also, this amazing complex contains a square and a circle with the same *area* (blue)*. *Both shapes enclose 20 acres. These measurements would require complex mathematical processes to calculate. Modern mathematicians would use pi to calculate these dimensions.