Nestled in the hills above the Loutre River in Montgomery County, Graham Cave State Park features an unusual sandstone cave that contained evidence that rewrote history books. Once used for shelter, Graham Cave became historically significant when archaeologists discovered how long ago human occupancy had occurred. University of Missouri archaeologists uncovered artifacts revealing human use of the cave dating back to as early as 10,000 years ago. Clues to the lifestyle of the ancient Dalton and Archaic period Native Americans were uncovered. Today, visitors are allowed in the entrance of the cave, where interpretive signs point out interesting discoveries. Surrounding Graham Cave is 369 acres of naturally diverse land designated as Graham Cave State Park. Several trails wind throughout the park's forests and glades. A boat ramp on the Loutre River provides access for boating and fishing. An open picnic shelter, playground areas and picnic sites make the park an ideal place for a day of family fun. For those in need of a longer retreat, a wooded camping area offers basic and electric campsites, modern restrooms and hot showers. Come explore the history that unfolded at Graham Cave and enjoy nature at Graham Cave State Park.
A really unique geological site to behold. Very quick and easy trip. Here's the info from the park-
"Graham Cave is unusual because it formed at a soft sandstone/hard dolomite contact. Because the St. Peter Sandstone has spaces to hold water, it acted first as a sponge. Water softened the cement holding the sandstone together and the rock was gently washed away over time, leaving an arched ceiling. The Jefferson City Dolomite floor dissolved also, though not as much as the sandstone. In most such contact caves, the dolomite is removed first, leaving a flat sandstone ceiling subject to breakdown. Graham is an excellent example of a rather unusual method of cave formation."