Again it is a pleasure to acknowledge the help of persons who have assisted in the development of this new edition of the journals. The individuals named in previous volumes have been a continuing source of help. Persons who have helped with this particular volume include Robert N. Bergantino (geology), Butte, Monana, and Lawrence L. Loendorf (archaeology), Grand Forks, North Dakota.
Beginning with this volume, the annotation makes extensive use of United States Geological Survey (USGS) maps. Bergantino graciously supplied the project with a set of USGS maps (1° x 2°, 1:250,000) on which he had plotted Lewis and Clark's route, camps, and points of observation through Montana. We used those maps principally for obtaining modern place names and did not cite them in notes. Since these maps did not always provide sufficient detail, we turned to other USGS maps (30° x 60°, 1:100,000), and these were cited in the notes; they are also listed in the "Sources Cited," at the end of this volume. We were also aided by three special sources. In July 1979, Bob Saindon prepared a special supplement for the Glasgow (Montana) Courier titles "Lewis and Clark in Northeast Montana." This material was especially helpful for the expedition's trip beween the Yellowstone and Musselshell rivers. The Bureau of Land Management has developed a set of maps for the Missouri River Breaks region, from James Kipp State Park to Fort Benton, Montana. Titled "Upper Missouri National Wild and Scenic River," these maps locate Lewis and Clark camps and other historic features on a modern projection. In 1984 Bergantino produced a special map of "The Great Falls Portage of Lewis and Clark, 1805–1806." In addition to aiding our annotation, it was also used in preparing this volume's map of the area. None of the three sources are cited specifically in the notes.