May 15, 2009
The photo above was taken at Fossil Falls in the Coso Range of California, in the autumn of 2008. My son climbed down into Fossil Falls to look at a petroglyph in what appeared to be a cave, and discovered that the hole carved out by an ancient water flow extended about 15 feet (nearly 5 m) from the top of the falls down to the "cave." You can see in the photo on the right that the water churned as a powerful whirlpool or eddy through the rock, carving out the swirling lines in the hardened lava. The normally rough basalt rock was polished as smooth as glass by this flow and reworked into a number of curious shapes. Fossil Falls formed when meltwater from receding glaciers in the Sierra Nevada Mountains, during the last ice age, was forced to flow over a basaltic outcrop.