Poet Joaquin Miller’s praise of the “great Marble Halls of Oregon” helped promote National Monument status for Oregon Caves in 1909.  Visitors today can join a guided tour for about $10 ($7 for children 16 and under), exploring narrow passageways and stairs to hidden rooms of cave formations.  For a free hike above ground try the Big Tree Loop, crossing a forested Siskiyou mountainside to one of Oregon’s largest Douglas firs. Pets are banned on all park trails.

The caves’ marble began as tropical island reefs in the Pacific Ocean. About 190 million years ago the advancing North American continent scraped up the island sediments to form this part of the Siskiyous. At first the land here was so wet that percolating ground water dissolved parts of the marble, forming pockets. When the land rose and the caves drained, dripping water gradually deposited calcite inside—much as a dripping faucet can stain a sink. Drips in the cave first form “soda straws,” thin tubes hanging from the ceiling. When the tubes get plugged, water runs down the outsides and forms thicker stalactites. If the drip is fast, it carries dissolved calcite to the cave floor to form a stalagmite.

Hunter Elijah Davidson discovered the cave in 1874 when his dog chased a bear into the entrance. Davidson lit matches to follow.  When the last match died he found his way out of the darkness only by crawling along a cave-floor stream. After word spread of his find, early entrepreneurs damaged the cave by encouraging visitors to break off stalactites as samples, sign their names on the walls, and hug the white dripstone columns, darkening the rock. A cave operator who took over in the 1920s hoked up his tours with ghost stories, colored lights, and hidden growling men in lion skins—the origin of the Grants Pass caveman mascot. To preserve the cave, the National Park Service now urges visitors not to touch anything in the cave. Lighting is dim to discourage the moss and algae that grow near artificial lights.

This chapter is an excerpt from 100 Hikes: Southern Oregon