Recessions of Lakes Lahontan and Bonneville that commenced ???13,500 14C yr B.P. were interrupted at {slanted equal to or greater-than}11,500 14C yr B.P. in the Lahontan basin and ???12,200 14C yr B.P. in the Bonneville basin by relatively large perturbations in lake level that persisted for ??? 2000 years. Minor glacial readvances in the Sierra Nevada and White Mountains of California-Nevada occurred during the latter half of this interval (between 11,000 and 9700 14C yr B.P.). The hydrologic response of Lakes Lahontan and Bonneville and the mountain glacial advances were concurrent with the Aller??d/Younger Dryas climatic intervals recorded in vegetational and glacial records of western and central Europe. ?? 1992.