In addition to Muir's theory that Yosemite Valley was created by glacial carving he also believed that there were still "living glaciers" in the high Sierra. In his August-October 1872, Yosemite Creek, etc. journal, he notes that the stakes he placed in a straight line across the McClure Glacier on August 21 were now pushed down the mountain indicating a moving glacier and not simply a patch of snow.