In the far southwestern corner of Oregon, about thirty miles south of Grant’s Pass, upon slopes of coast mountains and at an altitude of four thousand feet, is a group of large limestone caves which have been set apart by presidential proclamation under the title of the Oregon Caves National Monument. Locally they are better known as the Marble Halls of Oregon.
There are two entrances at different levels, the passages and chambers following the dip of the strata. A considerable stream, the outlet of the waters which dissolved these caves in the solid limestone, passes through. The wall decorations, and, in some of the chambers, the stalagmites and stalactites, are exceedingly fine. The vaults and passages are unusually large. There is one chamber twenty-five feet across whose ceiling is believed to be two hundred feet high.