A group of researchers using sonar to find shipwrecks on the bottom of Lake Michigan have found something far older than crashed cargo ships. They believe they’ve found a 10-thousand-year-old stone structure like Stonehenge, including a rock carved with the image of a mastodon. io9 pal Geoff Manaugh reports over at BLDG BLOG that the researchers’ report (with cool sonar images) was released last year to surprisingly little fanfare. And yet the possibility of a Stonehenge-esque worship site wouldn’t be out of place at the bottom of Lake Michigan. The region already has its share of petroglyphs from ancient tribes and other standing stone sites. These submerged stones could have been raised by local populations at a time when the lake bed was dry, in the late Ice Age. More research is needed to determine whether these stones were arranged by humans, or merely look that way.
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