At Grimes Point, where prehistoric natives carved petroglyphs on the surfaces of boulders along what at the time was the shore of ancient Lake Lahontan. The lake reached its highest levels at least four times between 75,000 and 10,000 years ago. We will see abundant evidence for this lake, such as shorelines carved by wave action and sediments deposited in the lake. We will see pebbles that are highly polished by natural tumbling along the shores of the lake. Today, remnants of Pleistocene Lake Lahontan include Pyramid Lake and Walker Lake.