By Brenna R. Kelly
The Cincinnati Enquirer

It's not every day you can see a natural type of concrete formed by a glacier more than 100,000 years ago - in fact, it's only one day.

On Saturday, a private nature preserve featuring one of the area's unique geological features will be open to the public from 10 a.m. to 4 p.m.

Split Rock Conservation Park is a 145-acre site on the Ohio River and Woolper Creek in Boone County named for large glacial deposits that look like a large rock cut in two.

The "rocks" are actually a conglomerate of many different rocks mixed together by glaciers to make a sort of concrete. The deposits were left near the river between 130,000 and 300,000 years ago, said Mark Jacobs, executive director of Split Rock.

Though there are other glacial conglomerates in the area, "this is one of the most prominent," Jacobs said. "But it has always been private land, so it hasn't been accessible to people."

But Saturday, for only the second time, the public will be able to explore the site along Woolper Creek and the river and learn about Boone County's history.

"It's a good opportunity for the local people to come and see what we are doing," said Jacobs, who lives at the park.

Saturday, visitors can explore trails through meadows, wetlands and along the river. A geologist will be on hand to explain the rock formations, and an archeologist will explain the history of the site. Kentucky forestry and wildlife officials will also be at the open house.

A historical re-enactor group, the Ole' Caintuckee Primitives, will camp on the site and show visitors how people lived before 1840.

The open house is also an effort to showcase the beauty of western Boone County, Jacobs said.

It's hoped the event will teach visitors "the value of conservation and historic preservation in western Boone County," Jacobs said. "Even in eastern Boone County, people don't know there's anything beyond Burlington."

The open house is also sponsored by the Boone Conservancy (a nonprofit land trust) and the Boone County Historic Preservation Review Board, which oversees the county's historic preservation policy.

Split Rock park is owned by Edgewood orthodontist David Quast and his wife, Patricia, and leased to Wildlife Conservation Kentucky Inc., a nonprofit corporation run by a three-member board.

The group uses Split Rock park to teach local students and other groups about conservation through interpretive hikes. Tours are available to groups by appointment.

In the year since Wildlife Conservation Kentucky was formed, about 1,000 visitors - including school field trips, Boy Scouts and garden clubs - have visited the park, Jacobs said. The park also held an open house last year.

In the early 1900s, the site was a popular picnic destination, with people rowing boats to the land and sitting on top of the large rock, Jacobs said. But in the last several decades, it has become a hidden treasure - with only a few people knowing it exists, he said.

"I lived in Boone County all my life and just became aware of it not too long ago," said Kim Adams, executive director of the Boone Conservancy. "It's a neat little secret."

Split Rock Park is at 4503 Belleview Road in Petersburg. For more information or directions, call (859) 689-9999 or go to www.splitrockpark.org.

E-mail bkelly@enquirer.com