Dr. A. C. Peale, 1849-1914
"Hayden also selected four young men who were recent graduates of the University of Pennsylvania, where he taught in the Medical Department. Three of these men had studied under him there, including Albert Peale, one of the diarists." 
"Albert Charles Peale, a member of the famous family of Philadelphia artists, took Hayden's course in geology at Penn and graduated with an M.D. in time to join Hayden for his first trip to Yellowstone. Hayden assigned him the task of writing up the first scientific analysis of the hot springs and geysers, and Peale's results spanned all three of Hayden's annual reports on Yellowstone." 
- Merrill, Marlene. With Hayden in the Field : a Case Study Based on Unpublished Letters and Diaries from the 1871 Yellowstone Survey. 1993. Yellowstone Research Center Archives.
- F. V. Hayden, Preliminary Report of The United States Geological Survey of Montana and Portions of Adjacent Territories; Being A Fifth Annual Report of Progress (Washington: Government Printing Office, 1872), pg. 4.
- William L. Chenoweth, "Albert C. Peale, M.D.—Pioneer Rocky Mountain Geologist," in Geology of Cataract Canyon and Vicinity, Tenth Field Conference, 1987, proceedings of Geology of Cataract Canyon and Vicinity, 1987, section goes here, accessed February 15, 2013, http://techplace.datapages.com/data/fcgs/data/018/018001/25_four-corners180025.htm.
- Mike Foster, Strange Genius: The Life of Ferdinand Vandeveer Hayden (Niwot, CO: Roberts Rinehart Publishers, 1994), pg. #228.