Before reaching Mount Thielsen, they passed over Diamond Lake. It was located in a valley between Thielsen and Bailey. Just why lakes should nestle in the valleys along the crest of this high mountain range, Bill could never understand. In California there is a long chain of lakes which extends from the middle of the state to the Oregon line. These lakes are also located amidst the highest peaks of the Sierras. It is a topsy-turvy condition of topographical features that allows water to be plentiful among the mountain peaks where it should run off, and have extremely arid land down in the plains.