If you have a comfortable pair of hiking shoes, Jad D'Allura would like to lead you on a hike late Sunday morning.

If you have a comfortable pair of hiking shoes, Jad D'Allura would like to lead you on a hike late Sunday morning.

But you'd better pack a lunch and bring something to drink. While it'll be just a short hike, he will be taking you back some seven million years to a time when lava flowed in the Rogue Valley.

A geology professor at Southern Oregon University, D'Allura will lead a group onto Upper Table Rock as part of the popular educational walks on Upper and Lower Table Rocks offered each spring by the U.S. Bureau of Land Management and The Nature Conservancy.

The weekend hikes, which begin Saturday and continue through May, will be led by experts on topics ranging from botany to birds and wildflowers to wildlife.

Because attendance is limited and hikes generally fill up, you may want to register quickly, suggested Molly Allen, environmental education specialist with BLM's Medford District.

"These are popular hikes because they are so close to Medford and the flat-top mesas are pretty unique here," she said, noting that about 40,000 people hike the Table Rocks each year.

Research by the Oregon Department of Geology indicates the twin mesas are what remain from an eruption of Olson Mountain, an extinct shield volcano immediately east of what is now Lost Creek Reservoir. Scientists explain that a shield volcano spreads lava across the ground rather than spewing it out of a cone. The Table Rocks are the last remnants of lava that once coated that portion of the valley floor, they conclude.

Growing on the Table Rocks are more than 75 species of wildflowers, including the dwarf woolly meadowfoam, a plant found only in this area, Allen said.

"The weather has been kind of cool, but with the forecast in the 70s later this week, a lot of the wildflowers are already up — they are just waiting for the sun to come out to bloom," she said.

In addition to a myriad of wildflowers, there are also vernal pools teeming with life, various creatures to see along the way and a spectacular view of the Rogue Valley.

The free hikes are three to five miles long on a moderate grade and last three to five hours. No drinking water is available. Restrooms are located at both trailheads. Dogs are not allowed on the trails. To reserve a space on a hike, call 541-618-2200.

BLM owns 1,280 acres on the Table Rocks, which were designated as areas of critical environmental concern in 1984. The Nature Conservancy established a nature preserve at Lower Table Rock 30 years ago and acquired 1,710 acres adjacent to BLM lands in 2009. A cooperative management plan covering about 4,870 acres of Table Rock land is being fashioned by the agency and the group.

To that end, students from the Southern Oregon University Research Center will conduct surveys on the trails of the Table Rocks over the next three months to gather information from visitors about what they enjoy about them and suggestions for improvements.