A group surveying underwater energy pipelines in Michigan believes it has inadvertently discovered signs of ancient Ice Age living.

The team of local indigenous residents had initially set out to examine Enbridge’s Line 5 oil and natural gas pipelines in the straits separating the Lower and Upper Peninsulas during an ongoing dispute over operations, the Detroit Free Press reported.

But when they sent a remote-controlled vehicle into the water for the project, they said they happened stones arranged in circular and linear patterns on the lake floor — an area that hasn’t been above water in about 10,000 years.

“We didn’t expect to find this — it was really just amazing,” said Andrea Pierce, 56, a citizen of the Little Traverse Bay Bands of Odawa Indian.

Pierce was among the four women who led the research into the pipeline toward the end of last month when the discovery was made.

Similar findings have come to light in recent years. John O’Shea, a University of Michigan archaeologist, found closely resembling stone formations under the water of Lake Huron back in 2009, according to the Detroit Free Press.

O’Shea found arranged stones, believed to be used to herd caribou, as well as fire rings and other evidence of ancient culture.

The group that made the discovery in the Straits said scientists and area tribes must validate the findings — and if they’re proven correct, the pipeline, known as the Enbridge Line 5, should be barred from operating if it disrupts culturally sensitive sites on the lake floor.

Enbridge spokesman Ryan Duffy told the Detroit Free Press the company had also surveyed the area around the pipeline and that it  “found no submerged cultural resources in the area that was assessed.”

“We have not seen the report from the organization suggesting they have discovered significant features and we do not know if they assessed the same areas we did,” Duffy continued. “We are open to sharing the information we have collected with tribal governments and learning more about the assessment done by this group.”