10 GEOLOGY OF THE BLACK HILLS. 



visited tiie Upper Missouri region, in whicli he spent two years, traversing 

 it in (lilTerent directions, often on foot. During this time he passed up the 

 j\Iissouri River to Fort Benton, and up the Yellowstone to the north of the 

 Bighorn River, and traversed large portions of the bad lands of the White 

 River region. 



In 1855 an expedition was made into the Dakota country, called the 

 "Sioux Expedition," under the command of General W. S. Harney. This 

 was unaccompanied by any scientific observer, and was undertaken primarily 

 to determine upon routes to the far west and between the frontier military 

 posts. A report of the exploration was made in a small document, "Explo- 

 ration in the Dakota Country," published by order of the United States Sen- 

 ate. In 1 856 these explorations were continued under the immediate com- 

 mand of Lieut, (now Major of Engineers and Bvt. Maj. Gen.) G. K. Warren, 

 of the United States Topographical Engineers, and he was accompanied by 

 Dr. F. V. Hay den as geologist and naturalist. Starting from Saint Louis, 

 Lieutenant Warren made a careful survey of the Missouri to Fort Pierre, 

 at Avhich place the expedition was organized. From this point the Missouri 

 was ascended in the American Fur Company's boat to some 60 miles above 

 the mouth of the Yellowstone River, careful examinations being made en 

 route. With wagons the Yellowstone was ascended for 100 miles above its 

 mouth, and with pack mules to the mouth of the Powder River, some 30 

 miles farther. The expedition returned to Fort Pierre by boats, mapping 

 the Yellowstone River, verifying the map of the Missouri, and examining 

 all interesting points. Lieutenant Warren was ordered in 1857 to continue 

 these explorations, and to detemiine the best route between the Big Sioux 

 and Fort Laramie and South Pass, and then to examine the Black Hills as far 

 as possible. This expedition is of particular interest here, because it obtained 

 the first reliable information regarding the Black Hills of Dakota, and a 

 more detailed notice of it w'\\\ not be out of place. 



Leaving Sioux City with wagons. Lieutenant Warren ascended the 

 Loup Fork to its source, and crossing to the Niobrara ascended it, and 

 thence reached Fort Laramie. Here his party divided, and one part, under 

 Lieutenant McMillan, with the wagons, descended the Niobrara, where it 

 awaited the main party. Lieutenant Warren, accompanied by Dr. Hayden 



