Editing Yosemite National Park (section)

===Glacial sculpting===
[[File:Glacially polished granite.jpg|thumbnail|Glacially polished granite [[cirque]] in upper [[Tenaya Canyon]]]]
A series of glaciations further modified the region starting about 2 to 3&nbsp;million years ago and ending sometime around 10,000 BP. At least four major glaciations occurred in the Sierra, locally called the Sherwin (also called the pre-Tahoe), Tahoe, Tenaya, and Tioga.<ref name="GeologyNP339"/> The Sherwin glaciers were the largest, filling Yosemite and other valleys, while later stages produced much smaller glaciers. A Sherwin-age glacier was almost surely responsible for the major excavation and shaping of Yosemite Valley and other canyons in the area.<ref>{{Cite web|title=Volcanoes of the Eastern Sierra Nevada|url=https://sierra.sitehost.iu.edu/papers/2012/klapperich.html|access-date=2021-06-28|website=sierra.sitehost.iu.edu|archive-date=June 28, 2021|archive-url=https://web.archive.org/web/20210628032933/https://sierra.sitehost.iu.edu/papers/2012/klapperich.html|url-status=live}}</ref>

Glacial systems reached depths of up to {{convert|4000|ft|m}} and left their marks. The longest glacier ran down the Grand Canyon of the Tuolumne River for {{convert|60|mi|km}}, passing well beyond Hetch Hetchy Valley. Merced Glacier flowed out of Yosemite Valley and into the Merced River Gorge. Lee Vining Glacier carved Lee Vining Canyon and emptied into Lake Russel (the much-enlarged ice age version of Mono Lake). Only the highest peaks, such as Mount Dana and Mount Conness, were not covered by glaciers. Retreating glaciers often left recessional [[moraine]]s that impounded lakes such as the {{convert|5.5|mi|km|0}} long Lake Yosemite (a shallow lake that periodically covered much of the floor of Yosemite Valley).<ref name="GeologyNP333">{{harvnb|Harris|1998|p=333}}</ref>