Lake Michigan Stones, photo by bldgblog.

In Stonehenge Beneath the Waters of Lake Michigan, Geoff Manaugh of BLDGBLOG writes:

In a surprisingly under-reported story from 2007, Mark Holley, a professor of underwater archaeology at Northwestern Michigan University College, discovered a series of stones – some of them arranged in a circle and one of which seemed to show carvings of a mastodon – 40-feet beneath the surface waters of Lake Michigan. If verified, the carvings could be as much as 10,000 years old – coincident with the post-Ice Age presence of both humans and mastodons in the upper midwest.

Regarding the slightly repurposed “sector scan sonar” device that Northwestern Michigan University professor and underwater archaeologist Dr. Mark Holley & Brian Abbott were using to survey some old wrecks when they made their discovery, Geoff writes:

The circular images this thing produces are unreal; like some strange new art-historical branch of landscape representation, they form cryptic dioramas of long-lost wreckage on the lakebed. Shipwrecks (like the Tramp, which went down in 1974); a “junk pile” of old boats and cars; a Civil War-era pier; and even an old buggy are just some of the topographic features the divers discovered.

You’ll definitely want to click through to read the rest and see more pictures!

You can read a detailed feature about this in U.S. archeologists find possible mastodon carving on Lake Michigan rock at NowPublic and listen to some radio reports from the time of the discovery in August of 2007 that include an interview with Dr. Holley and another with Grand Traverse Bay Ottawa Indian tribal member and historian John Bailey in Mammoth discovery beneath Grand Traverse Bay? on Absolute Michigan.