Select Page

Alvy McGraw told members of the Mound City Chapter of the ASO about a prominent sacred circle located just west of Chillicothe on the east bank of North Fork Creek. That was sometime in the late 1970’s. I recall he mentioned that it was being plowed for the first time in living memory with it having been within an orchard prior to that. He also mentioned that it was one of two circles located there that were mapped by Squier and Davis in 1847 (Squier, 1847).  See Figure 1 for a their map.I visited the site in the spring of 1975, and found it to have been fall-plowed with the soil literally flattened by the winter and spring rains. The large circle was bold with a deep and broad ditch. I marveled that it had survived in such good condition.

Steel Works earthworks Chillicothe

Figure 1. A portion of the Squier and Davis map of earthworks in the area of Chillicothe. The Steel Works are shown in the box on the lower left side of the map. Just two circular works are shown along with a mound that is no longer in existence.


The field was remarkable in being literally almost solid gravel with very little soil content, and it was absolutely absent of any cultural remains. This was a curious finding with that field being right above the North Fork of Paint Creek and above any normal flood levels. I walked very briefly over several fields south along the creek and found a Hopewell habitation site and evidence of other cultural periods. An older man, who lived in the house along the lane leading to the earthwork, gave me permission to walk the fields and he also told me artifacts could be found along the lane south of the earthworks.

In 1979 the field was again barren of any plants making it a good time for some aerial photography. I flew over the site (and on that day others in Ross and Pickaway Counties) in March of 1979 with my friend Dr. Paul Eastman at the airplane controls. Two cameras were used: one loaded with Kodak Ektachrome® Aero-infrared film and the other with Kodak Kodachromeô color slide film. The infrared film required the use of an orange filter, and exposing this film properly was more guesswork than craft and most of my exposures were under-exposed (dark).

The large circle and ditch showed up boldly on the color film, but were dark and muted on the infrared slides. I looked for the smaller second circle Squier and Davis showed on their map (Figure 1), but it did not jump out in the photos. I did note another circle just east of the large circle and I thought maybe Squier and Davis had been in error in their placement of it.

The color slide image is shown in Figure 2 and the infrared film image is shown in Figure 3. The infrared slides were dark, but with modern digital technology they could be made much more useable. They were scanned on an Epson photo scanner and then processed with Adobeô Photoshop® Elements 11 software. The digitally manipulated slides contained all the detail hoped for.  There are many suspicious features in both the infrared and color slide photos and particularly in the infrared one.



Steel Works earthworks

Figure 2. Aerial photograph of the Steel Works taken in March of 1979 with Kodachrome™ color slide film. The largest circle/ditch earthwork is plainly visible and other works are visible but less defined as to size and nature.


Steel Works earthworks

Figure 3. Aerial photograph of the Steel Works taken in March of 1979 using Kodak Ektachrome™ Infrared color slide film. Here the earthworks are better defined than those on the Kodachrome™ color slide film. Soil is rendered a green color and living foliage is reddish in color (note lawns around farm buildings).

Dr. Jarrod Burks flew over the site several years ago when the wheat (or oats?) crop was nearly ready for harvesting, and he noticed that some of the plants were still quite green and that they outlined possible small ditched earthworks. He subsequently surveyed the field with a magnetometer and discovered a plethora of smaller earthworks surrounding the large circle/ditch earthwork. One of his maps is shown in Figure 4 and it is seen from the same angle from above as were my aerial photos to better enable comparisons. Dr. Burks discovered at least nine smaller earthworks of many shapes and sizes and maybe even more! This field was an ancient ceremonial/social ground, and that might explain the gravelly soil – had it been intentionally covered with the gravel? Or was it an outwash from thousands of years of flooding? Hopefully that question will someday be answered. Burks did some high resolution surveying of the site and found a number of posthole circles separate from any earthworks.

In my photos there are several bold linear features that to my eye do not represent naturally formed features. They bear strong resemblance to Hopewell wall features visible at other earthworks. Burks has seen these features as well and considers them natural wash features, and this could be the case, but their linearities begs the question of whether they are natural or man-made. They could be plowing lines and definite ones are in the field holding the large circle/ditch (see caption for Figure 4). The crossed lines to the north could be the same thing, but they do not come from the corners of any existing field as do the southern ones and they are much bolder.

Almost all of the works Burks found by magnetometry are visible in my 1979 aerial photos. In 1979 magnetometry was still in the future and suspicious features in aerial photos remained just that, but with Burk’s geophysical work most such soil stains have proven to be cultural features. And, in fact, one can now find and reasonably assume that many such soil stains are probably earthworks because of Jarrod Burks’s pioneering work. Of course, surveying such features by geophysical means is the culminating proof of their cultural reality.

The aerials were taken after a storm system had passed through a day or two before, and the field is partially dry – the darker splotches are moist areas. Of interest is the center of the circle where it is still wet and darker and a square-like shape is apparent. Is this indicative of a structure of some sort, such as a square Hopewell type building? There certainly had to have been something in the center platform of that very dominant circle/ditch earthwork.

The infrared slides show many more features than have been delineated so far. Are these earthworks not detectable by magnetometry, such as walled enclosures absent ditches? Figures 4 and 5 compare the features delineated by Dr. Burks (Burks) with those seen on the infrared photo. Each work is given a letter in both Burks’s map and on my infrared photo: the earthworks seen on both photos are labeled with lower case letters and additional ones seen on the infrared photo are labelled with upper case letters. I detect eight more features that could be cultural features (L, M, N, O, P, Q, R and S). Feature “S” appears to be a large circle and feature “T“ looks like a wall. The other new possible features appear to be small circular ones without ditches. These possible features should be given some scrutiny in the future.

Steel circle view earthwork

Figure 4. Photograph of the large circle/ditch earthwork looking to the west. About two thirds of it are shown with the ditch and inner platform visible. This work is highly visible even here in 1975 after many years of plowing.


Steel Group earthwork map Dr. Jarrod Burks

Figure 5. Map of known works at the Steel Group as surveyed by Dr. Jarrod Burks using a magnetometer. Those in black and white are wall/ditch types and those circles shown in yellow are post circles. The features in blue are suspected works. The large circle/ditch work (a) is the largest work in the assemblage. The works are identified by lower case letters to serve comparison purposes with Figure 6. This map was generously shared with me by Dr. Burks.

Steel earthworks

Figure 6. This infrared aerial photograph has the individual works identified with letters: the smaller case works are the same as shown on Burks’ map in Figure 5. The large case letters designate possible works not yet delineated by any surface surveys. The bold linear feature designated by “T” looks like a typical Hopewell wall and the feature designated by “S” could be a large circle work. All the other possible features appear to be smaller enclosures. The infrared photo reveals a great deal of information and this technique should be used in any future surveys along with magnetometry.

The power of new technologies and older ones to uncover earthworks has resulted in a much richer appreciation of the Hopewell and Adena ritual landscapes. Magnetrometry is the new technology, and it has proven to be a powerful tool for finding plowed down earthworks and for truthing earthwork sites. But the old technology of infrared aerial photography is also a powerful tool in the search for earthworks, and now its power has been confirmed by the magnetometer surveys. Perhaps both techniques should be combined in future work?


Dr. Jarrod Burks kindly allowed me to use his most recent map of the Steel Works and Timothy Everhart has kept me informed of excavation details being carried out there. My thanks too to the late Alva McGraw for his information about this site and many others as well. Dr. Paul Eastman piloted the aircraft and his able maneuvering allowed for advantageous views of the earthworks.


Burks, Jarrod
“New Magnetic Gradiometer Survey of the Steel Group Earthworks, Ohio, USA”, ISAP News, Issue 51.

Squier, E. G. and Davis, E. H.
Ancient Monuments of the Mississippi Valley, The Smithsonian Institution, June, 1847