Fossil Falls is a geologically and historically distinctive place. Volcanic action, along with glacial meltwater, helped to produce this waterfall. It lies about 40 miles south of the town of Lone Pine, almost entirely off Road 395 (JoshMc). The Sierra Nevada Mountains formed glaciers during the Ice Age.
The meltwater from the glaciers formed lakes, some of which were enormous, such as Owens Lake, which no longer exists. At the same time, the river of the same name was created. Its route has been altered multiple times due to volcanic activity (National Park Service). This waterfall was created when the river was forced to diverge again and run through the basalt layers, polishing and shaping the rocks into numerous distinct forms. All of Fossil Falls’ volcanic eruptions are basaltic.
The Coso Volcanic Field delivered flows from the northeast, and subsequently, Red Hill, seen from Fossil Falls, discharged newer lava. The floods occurred between 400,000 and 10,000 years ago (JoshMc). During this time, glacier flows swept over Fossil Falls, flattening the vesicular basalt. The youngest glacial flow eroded Fossil Falls, Tioga, in the Sierra Nevada mountain range around 20,000-10,000 years ago (JoshMc). The basalt contains not just microscopic gas bubbles but also significant, perfectly round holes. These are erosional landforms known as potholes.
Red Hill is assumed to have thrown granite debris, which fell into Fossil Falls. The water accelerated as it passed the boulders, and the calmer water ahead caused it to pause and spin, forming a whirlpool. The high-velocity currents were strong enough to capture the granite chunks from Red Hill and spin them down in various eddies, boring them into the basalt. The silt was trapped and continued to erode the holes in a circular pattern (National Park Service). The fossil waterfalls originated downstream from where they are now. In turn, water flowing over the falls’ edge undermined them, causing them to travel upstream and become taller.
Artifacts and rock art from the Fossil Falls region reveal the culture that lived there. Native American tribes like the Coso lived in this area as early as 10,000 to 20,000 years ago, camping beside the now-dry river. They collected resources and hunted the incredible animals that were present during the period. When the lakes and rivers dried up, the large animals became extinct, forcing humans to relocate and alter their lifestyles in search of fresh game and food sources.
However, when the temperature returned to a more moderate state, about 4000 B.C., Native Americans began migrating back to the area (National Park Service). They established a new culture that stressed the use of the resources available in the desert. The manner of life these people followed lasted until the nineteenth century, when a nearby tribe, the Little Lake Shoshone, first came into contact with Europeans (JoshMc). Flakes of obsidian may be found in the region where Native Americans lived near Fossil Falls and in the Coso Mountains, where they gouged obsidian to make their implements.
Today, volcanic rocks have been extracted on Red Hill. When molten lava spilled through a breach in Earth’s crust, it cooled rapidly, forming a porous rock known as slag. The slag collected around the vent, forming the cone-shaped mound you see today. The slag is utilized for a wide range of economic uses. The Fossil Falls Archaeological District is part of the National Register of Historic Places. The Bureau of Land Management classifies Fossil Falls as an Area of Critical Environmental Concern. This location is off-limits to the removal of Native American artifacts.
Works Cited
JoshMc. “Fossil Falls: Dry Waterfall on Highway 395.” California Through My Lens, 2022.
National Parks Service. “Geologic Formations.” National Parks Service, U.S. Department of the Interior.