Jug Rock

The biggest free-standing table rock east of the Mississippi

Jug Rock stands alone in quiet woods along Highway 50 just north of Shoals, in Martin County, Indiana, in the valley of the East Fork of the White River. It is a pillar of sandstone with a flat slab balanced on top, and it is the largest free-standing table rock, or mushroom rock, in the United States east of the Mississippi. It looks, if you squint, like a jug, and the slab on top has long been called the stopper.

The stone belongs to the Mansfield Formation, laid down in the Pennsylvanian between roughly 325 and 286 million years ago. Over time erosion worked along fractures in the rock and cut the pillar loose from the cliff beside it. A companion, House Rock, stands across from it, and a little way off a high ridge of the same rock ends near the river in a crag once called the Pinnacle.

The state geologist E. T. Cox described the scene in his Second Report of the Geological Survey of Indiana in 1871. Near Shoals, he wrote, a ridge of millstone grit ends within a few yards of the river, its top crowned by a projecting mass of conglomerate sandstone standing 170 feet above the stream, with cyclopean blocks broken off and lying at its foot in every conceivable position. On the north side, disintegrating forces had left a tall mass of rock standing apart from the ledge. He measured it at 42 feet, noted the irregular false bedding just above the bulge of the jug and the quartz pebbles packed into its lower half, and used a photograph of it, taken by D. Allbright of Shoals, as the frontispiece of the volume.

It is easy to miss in the leaves of spring and summer. There is a tiny gravel pull-off on Highway 50 at Albright Lane, and a steep walk down to the base. The rock has given its name to the Shoals High School teams, the Jug Rox, whose mascot is the Roxer Boxer.