1841 Map of Mammoth Cave by John S. Wood, M.D, from The American Magazine.
1841. Wood, John S. M.D. 1841. Chart of the Mammoth Caves, p 86- 90, 130-133, 184-190, The American Magazine, and Repository of Useful Literature, Volume 1, Issue 3, published by B. Wood. http://books.google.com/books?id=w48eAQAAMAAJ&dq