Larger Horseshoe Shaped Earthwork Diagramed at Portsmouth, Ohio "The Door of Life"
The horseshoe symbol was used as an ancient religious symbol in Assyrian and Egyptian hieroglyphs meant to signify the enigmatic “door of life”.
Late 1800s Scioto County, map depicts a third horseshoe-shaped earthwork to the south as large as the two above it to the north.
Map drawn by Squire and Davis in 1846 for "Ancient Monuments of the Mississippi Valley" shows the earthwork's opening facing the northwest and much smaller.