Northern Prairie Wildlife Research Center
This expedition was led by Captain Ludlow with George Bird Grinnell as its naturalist. This expedition followed the Carroll Trail from Fort Carroll on the Missouri River to Helena and then proceeded to Yellowstone National Park (Figure 21). Grinnell's report is an excellent documentation of wildlife and habitats encountered through this section of Montana. In addition, Grinnell had time for an excursion from Fort Carroll up to the Little Rocky Mountains and reported large numbers of bison and pronghorn in this area.

Grinnell, G.B. 1876. Report of a reconnaissance from Carroll, Montana to
Yellowstone National Park and return. by William Ludlow, U.S. Govt.
Print. Off. Washington, DC. Zoology 640-655.
Ludlow, W. 1876. Report on a reconnaissance from Carroll, Montana Terr.
on the upper Missouri to the Yellowstone National Park and return,
made in the summer of 1875. War Dept., Washington.
McFarling, L. 1955. Exploring the northern plains, 1804-1876. Caxton,
Caldwell, ID.