Geologic Trip, Tuolumne Meadows
Olmstead Point is in Tenaya Valley on Highway 120 about one mile south of Tenaya Lake. During the glacial episodes the Tenaya Valley was filled with the Tenaya glacier which was moving from the Tuolumne icefield toward Yosemite Valley. As the glacier slid down the valley, it scooped out the depression now filled by Tenaya Lake and also smoothed and polished the hard granodiorite at Olmstead Point.
When the glacier melted, it left numerous glacial erratics lying on the surface of the polished granite. You can see good examples of glacial polish and erratics by taking the 1/4-mile nature trail from the parking area to Olmstead Point.