Vickie Carson, public information officer at Mammoth Cave National Park, illuminates what might be petrified wood (below) in an unused passage of the cave Tuesday. Photo by Miranda Pederson

George Gregory, a ranger at Mammoth Cave National Park, is about to retire. Before he does, hes passing on some ideas for scientists to study in the cave. While reading a book written in the 1800s about a visit to the cave, he came across a passage referring to some logs that could be petrified wood at a place called Sylvan Avenue. Sylvan Avenue is thought to have been named for what appears to be a number of limestone logs lying irregularly in the cave passage and resembling petrified wood, Gregory said. The passage in The Suckers Visit to Mammoth Cave is just a passing reference to some logs lying irregularly upon the floor, and bearing a perfect resemblance to petrified wood. Chris Groves, an associate professor of geography and geology at Western Kentucky University, said by visual inspection, the logs look like petrified wood, but things are not always what they appear. He said additional study of the site is in the planning stages with the park and Western. You have to be careful not to jump to conclusions, Groves said. He said the first step is to determine if it is petrified wood and then determine how the wood got there. Groves said most of the fossils in the limestone of the cave are from ocean areas that used to cover the area about 350 million years ago when the cave was formed. Its unusual to find wood in sediments like that, Groves said. There are several mechanisms where you could find wood. Groves said if this is petrified wood, logs could have floated down a river and into the ocean, become waterlogged and sank, or the shoreline could have been close to the area where the logs were deposited. Geography and geology associate professor Mike May hasnt seen the logs, but his educated guess is that it is probably a formation called stylolites, which are often confused for petrified wood. Theyre real common, May said. Stylolites are formed when stress on the rock causes some of it to dissolve, leaving behind clay and organic material in stripes, resembling wood. May said probably 98 percent of the time, something that looks like petrified wood is actually a stylolite formation. The logs, if they are petrified wood, could tell scientists about what the region was like when the cave was formed. The more we know about the time the cave was formed, the more we can find out about the cave, Groves said. The cave is full of all types of strange things that have not been studied, Groves said. The cave is so vast that its a lifetime to learn about it, Groves said. Its a global treasure. That cave is just magical. Groves has been exploring and studying the cave for about 20 years and he just heard about this possible petrified wood a few months ago. It is not far off the Historical Tour. It never ends being fascinating for some people, Groves said.