Very unusual map of part of Montana with the route of Lewis and Clark and notes on the hardships of the passage. Several Indian tribes are located (along with their population). There are no towns or settlements shown, although it covers the region of present-day Missoula and Great Falls. There was only one edition of this monumental work. Each sheet covers an area of approximately 20 degrees Longitude (from Paris) and 6 deg. of latitude. This was the first atlas in which all maps are made on the same scale of 1: 1,641,836. Ref: Koeman III Vdm 1 and Phillips' Atlases #747.