Question: The Black Mountains, a mid-Miocene formation, in which U.S. State, are a series of rugged, arid rocky volcanic mountains ranging in elevations to 3310 ft, the range lies on the north shore of Lake Mead, the largest reservoir in the United States in terms of water capacity?
Sentence (from "Boulder Wash"): Its source is at at an elevation of 2,841 feet / 866 meters in the Black Mountains.
Relevant evidence: No