Between Bogus Creek campground and Steamboat Creek is a stretch of 20 to 35 million year old volcanic rock. The columns were formed by the way the hot lava cooled. Over the eons, erosion has carved rugged ridges and ravines, exposing the andesite rock often found in western Cascade mountains. The columns and ridges of ancient rock are what gives North Umpqua River its scenic beauty, challenging whitewater and excellent summer Steelhead trout fly-fishing opportunities.