On the eastern side of the Sierra Nevada range lies Mono Lake, a remnant of a prehistoric sea that filled the valley below Tioga Pass. Once famous for the millions of migratory birds that stopped here on their travel and the Pacific gulls that nested in the millions, Mono Lake suffered from Los Angeles siphoning off water from the melting snowpack that feeds the lake. Threatened with disappearance, the lake is slowly recovering after efforts by conservation groups to wrestle the water supply away from the metropolis almost 400 miles away. Nonetheless, the numbers of birds using Mono Lake for resting, feeding and nesting has dropped significantly as they seek other havens in this desert environment.
Mono Lake is famous for its tufa formations (images of those later), remains of thermal vents in the lake’s bottom that are gradually exposed as the water level drops. The two islands in the lake and the chain of craters to the south are symbols of the younger and more violent volcanic activity in this valley. Although Mono Lake is probably over 1 million years old it sits on unstable foundations. Water passing through these younger strata pick up minerals, contributing to a salinity several times greater than the ocean and an alkaline nature that Mark Twain commented on as being useful for cleaning clothes by simply dipping them in the water a few times!
Little towns string along the eastern Sierra foothills, agricultural oasis catering to the constant tourist flow passing through in admiration of the scenery to the west.