Mound City’s overall shape is a square with rounded corners resembling the houses under its mounds. Until recently it seemed unique among earthworks. But archaeologist Jarrod Burks has discovered several now-invisible earthworks that were drawn as circles by nineteenth century explorers, but have been proven by modern remote sensing to be squares with rounded corners:

Perhaps all these old maps, say, Squier and Davis or the other publications that show a circle: it seems that a significant number of these circles aren’t circles, they’re actually squares with rounded corners. That’s significant because especially Mound City seems to appear out of nowhere, when in fact that’s not true: there seems to be a lot of other earthworks with these shapes, these squares with rounded corners.

A section of Dr. Jarrod Burks’ new data from the Junction Group near Chillicothe, with its “squircle” (square with rounded corners) shaped earthwork.