Archive for Lidar

The Reconstruction and Archaeoastronomy of a Hopewell Geometric Earthwork in Ohio


by Richard D. Moats


The Salisbury brothers authored a paper in 1862 describing several archaeological sites in Ohio. One was an “Ancient Symbolic Earth Works” in Northern Perry County. The paper included a narrative and plot map of a hill top earthwork and three associated features. They recorded linear measurements, angles of intersection, and mound elevations. They described five structures with flat tops which they termed “platforms” and another as an open “C” shaped structure (Salisbury and Salisbury 1862). State Archaeologist Warren K. Moorehead published a short article in 1896 describing the site naming it “Frank Yost’s Mounds” after the landowner. The only significant information he added to the Salisbury paper was finding ash in what he termed the “bird effigy” located inside a large circular enclosure. (Moorehead 1896).

Moorhead’s report did not contain the detail or descriptions of the entire structure as described in the Salisbury document. This indicates erosion and intentional agricultural destruction began in the latter half of the 19th century. Until recently, the large circle with an internal crescent and a small nearby mound are the only features known to exist into modern times. It is obvious the site was a large geometric earthwork similar to other Hopewell sites in Ohio. However, some features and therefore functions are unlike any other known Hopewell site, making this a very unique and important site.

This paper encompasses the rediscovery of lost features, digital reconstruction of the site, and investigation into its functions. I will show how the site integrates distant terrestrial features and offer my research into the purpose of this three dimensional geometric earthwork. I will demonstrate how precise construction and spatial orientation of the structure provided alignments with celestial body rise and set points. I will describe the visual illusions created by celestial body rises and settings in relation to the earthwork and a distant terrestrial feature. I will also suggest hypothesizes for the cognitive precursors for these Native Americans to construct such an elaborate structure.

Site Reconstruction:
The geographic center of the site, 33Pe5 in the Ohio Site Registry, known today as the “Yost Works”, is located on a hill top at coordinates 35°54’02”N x 82°20’31”W in Northern Perry County, Ohio. To the south of site center is an intact large circular enclosure and a small nearby mound both covered by trees and brush. Inside the enclosure on the south interior perimeter is an earthen crescent with a central “bulge” which, when viewed from above resembles an effigy of a spread wing bird. Until recently, these are the only features of the geometric structure known to have survived. Construction of an accurate site plot map began with entering the linear measurements generated by the Salisbury’s into a Computer Aided Design Program, (CAD). Scale and orientation needed to be verified before an accurate reconstruction could be completed. Dr. William F. Romain provided aerial LiDAR, images of the site. LiDAR is an acronym for Light Detection and Ranging. By filtering the digital LiDAR data in bare earth mode, foliage was eliminated and subtle terrain elevations were delineated. (2008a, 2008b. Romain and Burks).


Figure 1 LiDAR image revealing earthwork features. Image by W. F. Romain, Interpretation, R. Moats

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