ABSTRACT From 1840 to 1845, Roderick Murchison (1792–1871), an accomplished geologist who was instrumental in developing the Paleozoic portion of the geologic time scale, traveled in Europe, Scandinavia, and Russia, where he documented the occurrence and extent of the Silurian, Devonian, and Permian Systems. A key component of his fieldwork methodology was to examine fossils in both private collections and public museums to assess the types of fossils that occur in a region, in order to guide and expedite his mapping efforts. While working in Scandinavia, he examined fossil collections in Copenhagen, Oslo, Stockholm, Upsala, and Visby, and those collections clearly influenced his choice of travel routes and, ultimately, the geologic map (plate VI) in The Geology of Russia (Murchison et al., 1845). Furthermore, he was able to compare the Scandinavian fossils to British collections, thereby confirming the age of the strata he was mapping. The results of Murchison’s work appeared in numerous papers as well as two major books, The Geology of Russia (Murchison et al., 1845) and Siluria (Murchison, 1854), thereby advancing knowledge of Scandinavian stratigraphy. Not only were the fossil collections in the museums of his day essential to Murchison’s scientific research, but collections of documents in modern archives are invaluable in reconstructing his movements, observations, and discoveries more than 170 years ago, thereby demonstrating the utility of collections and museums to the construction of knowledge.