Fossil Falls is a unique geological feature near Little Lake, California.  Here the Owens River used to flow here during the Ice Age.  Glacial meltwater from the Sierra Nevada created large lakes & rivers in the area & this lava flow was carved by the prehistoric river.  The lava flows themselves were formed anywhere from 10,000-400,000 years ago.  Look carefully to see the smooth lava rock polished & gutted w/ potholes as the water churned through this canyon before tumbling over a 30 foot drop in the distance.  The site is on the national register of historic places as it is also an archaeological site from the Coso People long ago.  A similar geological feature is Dry Falls in Washington State, carved by the Missoula floods.