This World Wide Web page written by
Dan Styer;
http://www.oberlin.edu/physics/dstyer/Muir/FirstSummerResources.html;
17 March 2020.
Map of the Yosemite Valley by C. King and J.T. Gardner, 1865. (From Yosemite Guide-Book by Joshia D. Whitney, 1870 edition).
Map of a portion of the Sierra Nevada adjacent to the Yosemite Valley by Charles F. Hoffmann and J.T. Gardner, 1863-1867. (From The Yosemite Book by Joshia D. Whitney, 1869 edition).
Topographical Map of the Yosemite Valley and Vicinity by George M. Wheeler, 1878-1879.
Early Topographic Quads of California.
The Yosemite Book, by Josiah D. Whitney (1869).
General Benjamin Alvord, a military man and a mathematician.
Retracing work of an anonymous Japanese Muir enthusiast. Translated into English. (Includes photos of the presumed altar boulder, visited by Muir on 14 June 1869.)
Walking with Muir across Yosemite by Thomas R. Vale and Geraldine R. Vale.
The Mossy Boulder by Sharon Giacomazzi. (Visit to the altar boulder in 1997.)
Searching for the lost Mono Trail.
Unfortunately, Holmes himself obscures two facts: first that Muir's summer 1869 trip was his second trip to the Sierra (the first being in May and June of 1868); second that most of the summer 1869 trip was in the high Sierra, not in Yosemite Valley.