From Squier and Davis, Ancient Monuments of the Mississippi Valley (1848)
At top, the yoke is between the two paths. Photo: Jarrod Burks, via drone camera
The yoke is at bottom right. A berm forms the oval head, in the middle of which is a capsule-shaped mound a few feet high.
Assuming the Great Serpent is a reflection of a figure in the sky, we look for a serpent-like arrangement of stars with its head pointing westward — i.e., a reversed image of the Squier and Davis drawing.
Winter constellations visible from Ohio.
The head is centered on the 3.5 magnitude star Wasat, a spectacular sight in 1066 when occulted by Halley’s comet. A necklace of faint stars forms the yoke. The coil of the tail, including a few stars from Canis Major, ends on the brightest star in Puppis (Naos).
The hourglass shape of Orion has a rough counterpart in the Fort Ancient earthwork, not far from Cincinnati.
The Bayeux tapestry (scene 32) shows amazed observers pointing at Halley’s comet above a tower. In the night skies of January–March 1066, the spraying “star” passed through the middle of the oval head at Gemini.