Basin and Range thumb|upright=1.25|Mono Lake To the east of the Sierra is the Basin and Range geological province, which extends into Nevada. The Basin and Range is a series of mountains and valleys (specifically horsts and grabens), caused by the extension of the Earth's crust. One notable feature of the Basin and Range is Mono Lake, which is the oldest lake in North America. The Basin and Range also contains the Owens Valley, the deepest valley in North America (more than 10,000 feet (3 km) deep, as measured from the top of Mount Whitney).
Basin and Range thumb|upright=1.25|Mono Lake To the east of the Sierra is the Basin and Range geological province, which extends into Nevada. The Basin and Range is a series of mountains and valleys (specifically horsts and grabens), caused by the extension of the Earth's crust. One notable feature of the Basin and Range is Mono Lake, which is the oldest lake in North America. The Basin and Range also contains the Owens Valley, the deepest valley in North America (more than 10,000 feet (3 km) deep, as measured from the top of Mount Whitney).