It is not evident that information given by Gunnison and De Smet or any of their predecessors relative to unusual phenomena on the Upper Yellowstone greatly impressed representatives of the Federal Government. Certainly no eagerness to verify these reports is betrayed in the official instructions dated April 13, 1859, by which Captain Raynolds, Corps of Topographical Engineers, was directed “to organize an expedition for the exploration of the region of the country through which flow the principal tributaries of the Yellowstone river, and of the mountains in which they, and the Gallatin and Madison forks of the Missouri, have their source.” However, since one of the objects of this exploration was to ascertain the principal topographical features and since, moreover, the indispensable Bridger was secured as a guide, it would seem that the Yellowstone marvels were just about to be officially discovered and proclaimed. Not so, however. The expedition left winter camp on Platte River in May 1860. While a detachment under Lieutenant Henry E. Maynadier went north along the eastern slope of the Absaroka Range, the main party ascended Wind River to Union Pass, then turned north seeking the headwaters of the Yellowstone. Deep snow and a great “basaltic ridge” blocked their efforts before they reached Two Ocean Pass, and they had to satisfy themselves with encircling the Park area via Jackson’s Hole, Teton Pass, Henry’s Fork, and Raynolds’ Pass. By way of the Madison, they rejoined Maynadier at the Three Forks. Raynolds’ report and map became the first recognition by the Federal Government of the possible existence of volcanic activity in the region of the Upper Yellowstone. For information regarding the “burning plains, immense lakes, and boiling springs” and other unverifiable phenomena mentioned he was, of course, indebted to his guide Bridger, with trimmings added by Meldrum. On his “Map of the Yellowstone and Missouri Rivers,” within the “enchanted enclosure” which now constitutes Yellowstone National Park, the soldier-explorer had the courage to place “Yellowstone Lake,” “Falls of the Yellowstone,” “Burnt Hole,” “Sulphur Mountain,” and “Elephant’s Back Mt.,” all now recognizable features. This was an extraordinary demonstration of faith in Bridger’s veracity. Because of the Civil War, publication of the report was delayed until 1868, but the map itself was first issued separately a few years earlier.