Even more illuminating to the historian than the well-known De Smet letter are five unpublished maps traced by that missionary. These maps had little contemporary influence and, though noted by his biographers in 1905, they have been neglected by subsequent historians. They are documents of signal import, which should inspire renewed respect for the ubiquitous Bridger and yet increase the stature of the versatile and indefatigable De Smet, already one of the giants of western history. Of these five maps four are still at St. Louis University, which was his headquarters. These are among dozens which were made by him in the course of his several western journeys, the information obtained by acute personal observation as well as “from trappers and intelligent Indians.” The draftsmanship of the first three, while not striking, is respectable. One shows “Yellow Stone” River and tributaries as high as “Gardner’s F.” A second, embracing the Upper Missouri, Yellowstone, and Upper Platte regions, shows a nameless bladder-shaped lake at the head of the Yellowstone and a conspicuous “Hot Sulphur Spring” north of the lake. A third, embracing the entire West from the Great Basin to the Forks of the Platte, shows essentially the same features. The fourth map in the St. Louis collection is the most intriguing. This depicts that remarkable twisted region of the Rocky Mountains where the headwaters of the Yellowstone, the Wind, the Green, the Snake, and the Missouri rivers unwind before rolling to their respective oceans. The undated map is crude and smeary, and it has all the ear-marks of being sketched in the field without benefit of desk or blotter. In view of De Smet’s express testimony that the most famous trapper of all supplied him with his geographic data, at least for the “Yellowstone Park” section, it is a fair guess that this was drawn by De Smet with Bridger at his elbow. Here, on a rough chart consigned to the oblivion of a library vault, is where “Yellowstone Park” first comes into clear focus. Allowing for pardonable distortions, all of the principal scenic features are in evidence: the geyser basins of the Firehole (“volcanic country”); Mammoth Hot Springs (“Sulphur Mountain” near “Gardener’s Cr.”); a shapeless Yellowstone Lake (“60 by 9”) with “Hot Springs” and “Great Volcanoes” alongside; the Grand Canyon and “Falls 290 feet”; and Hayden Valley (“Volcanic country [?] Steam Springs”). Two Ocean Pass, Jackson Lake, and “Colter’s Hell” on Stinking River are other conspicuous features near by.