The Wisconsin Legislature mandated the fifth incarnation of the geological survey in 1873 to conduct a “complete geological, mineralogical and agricultural survey of the state.” Between 1873 and 1882, the fruits of this survey’s labor were published under the leadership of T.C. Chamberlin in the four volumes entitled Geology of Wisconsin. The volumes contain more than 3,000 pages of text, color lithographs, maps, and detailed engravings that comprehensively illustrate the overall knowledge of the geology and natural history of Wisconsin in the late 1800s. The accompanying atlas has also been digitized. Unfortunately, these books have long been out of print. Because of their historic value, the University of Wisconsin Digital Collections has scanned them and made them available on-line.