Nature

The rock forming Rocky Arbor's gorge is sandstone that geologists have aged at about 500 million years. The rock's sand grains are thought to have been deposited by rivers draining into shallow seas. The seas receded and the sand compacted into sandstone.

Eons later, the Wisconsin River cut a gorge through this stone and thus formed the park's picturesque rock walls and ledges.

The river has long since changed its course and now flows about a mile and a half to the east. The tiny stream that now occupies the gorge flows in the opposite direction that the mighty river did when it carved this scenic area.