In the spring the Indians throughout the buffalo country burned off the old grass in places where they had not used a fire drive in the previous autumn. On March 6, 1805, ''A cloudy morning & smokey all day from the burning of the plains, which was set on fire by the Minetarries for an early crop of grass, as an inducement for the buffalow to feed on." Until the new grass attracted the herds, the Indians hauled in the animals drowned in the river during the winter:
The ice has stopped running owing to some obstickle above… but few Indians visit us today. They are now attending on the river bank to catch the floating buffalow.
The obstickle broke away above & the ice came down in great quantities…. I observed extraordinary dexterity of the Indians in jumping from one cake of ice to another, for the purpose of catching the buffalow as they float down many of the cakes of ice when they pass over are not two feet square. The plains are on fire in view of the fort on both sides of the river. It is said to be common for the Indians to burn the plains near their village each spring.
As the explorers traveled up the Missouri, camping at night on the bank, they found that a stray buffalo bull could be a real danger:
Last night we were alarmed by a new sort of enemy. A buffaloe swam over from the opposite side and to the spot where lay one of our canoes, over which he clambered to the shore; then taking fright, he ran full speed up the bank toward our fires, and passed within eighteen inches from the heads of some of the men, before the sentinel could make him change his course; still more alarmed, he ran down between four fires and within a few inches of the heads of a second row of men, and would have broken into our lodge if the barking of the dog had not stopped him. He suddenly turned to the right and was out of sight in a moment, leaving us all in confusion.
As they passed through the Missouri River "breaks" near the mouth of the Judith River they saw a large buffalo jump. The herd had been chased across the level ground above a rimrock cliff.
Today we passed on the starboard side the remains of a vast many mangled carcasses of buffalow which had been driven over a precipice of 120 feet by the Indians and perished; the water appeared to have washed away a part of this immense pile of slaughter and still there remained the fragments of at least a hundred carcasses they created a most horrible stench… for this purpose one of the most active and fleet young men is selected and disguised in a robe of buffaloe skin, having also the skin of the buffaloe's head with the years and horns fastened on his head in the form of a cap… the part of the decoy I am informed is extremely dangerous, if they are not very fleet runners the buffaloe tread them underfoot and crush them to death, and sometimes drive them over the precipice also where they perish in common with the buffaloe.
When a buffalo cow in good condition was killed, the strips of back fat helped make a special dish, called white pudding:
… from the cow I killed we saved the necessary materials for making what our cook Charbono calls boudin (Powdingue) blanc … this white pudding we all esteem as one of the greatest del[ic]acies of the forrest…. About 6 feet of the large gut of the buffaloe is the first mo[r]sel the cook makes love to, this he holds fast at one end with the right hand, while with the forefinger and thumb of the left hand he gently compresses it and discharges what he says is not good to eat… the mustle lying under the shoulder blade next to the back, and the fillets are next saught, these are needed up fine with a good portion of the kidney suet; to this composition is then added pepper and salt and a small quantity of flour. [The intestine is then tied at one end, turned inside out and stuffed with the mixture. The other end is tied.] It is then baptised in the Missouri with two dips and a flirt and bobbed into the kettle; from whence, after it be well boiled, it is taken and fryed with bears oil until it becomes brown….
Twice in the following weeks Lewis lamented that the party was reaching the limits of the buffalo range and would have no more white pudding.
Lewis found that the Teton band of the Sioux held two small stretches of the west bank of the Missouri, one at the mouth of White River, the other at the mouth of Cheyenne River. The Tetons claimed the hunting grounds up both these rivers to their heads. They lived in tipis the year around, and planted no gardens of any kind, trading with the farming villages for any corn and beans they needed. They were much too far from the wild-rice country of the other Sioux bands either to harvest rice or buy it. Lewis disliked the Tetons from the first, finding them difficult to deal with. In his notes he stated that they were the vilest miscreants of the savage race, and he predicted that they would cause trouble in the future until subdued by force. However, he had no serious trouble with them.
On the entire trip from St. Louis to the Pacific coast and back, the party had real trouble with only one tribe, the nomadic Blackfeet. On the return trip in July 1806, Lewis with three companions went north from the Sun River in central Montana to the Marias River to learn if that stream headed north or west. He hoped that Marias Pass, mentioned by some of the Indians, might prove to be a shorter and better way to the west than the one he had just traveled.
After sighting Marias Pass, a deep notch in the continental divide, Lewis moved down the Marias River toward the Missouri. Along the way he met a party of eight Blackfeet who seemed friendly at first, but the next morning they tried to steal his guns and horses. In the resulting struggle two of the Blackfeet were killed. The rest retreated hastily, leaving behind most of their gear and a few of their horses.
The returning explorers met some fur traders moving up the Missouri from St. Louis, who assured them that their brush with the Blackfeet was of minor importance, for all the other tribes had been friendly, or at the most, indifferent to the explorers. The traders then continued upriver to their winter trading places, and returned to St. Louis with large packs of good furs. This stimulated the interest of other groups in the upper Missouri.
One of the new groups was led by Manuel Lisa, an important figure in the Missouri fur trade for many years. In the spring of 1807 he left St. Louis with a keelboat-load of trade goods, hoping to reach the rich fur country in the Montana mountains ahead of all competition. At the mouth of the Platte River he had a stroke of luck. Down the river came a dugout canoe, its lone occupant John Colter, who had been with Lewis and Clark. Lisa immediately signed Colter on as his guide and followed him up the Missouri, then up the Yellowstone to the mouth of the Bighorn River, in Crow country. Here Lisa built his trading post and sent out his trappers.
Colter took a single companion, John Potts, and set out up the Yellowstone along the path followed by the buffalo herds, the same trail Colter had traveled eastward with William Clark a year earlier. They crossed through Bozeman Pass to the Gallatin Fork, then went down to Three Forks and began trapping in the river bottoms there.
On a crisp summer morning about the end of July, with a morning fog on the river, Colter and Potts were in a canoe lifting their beaver traps when they heard the trampling of many hooves. They hoped for a harmless herd of buffalo, but when the fog drifted away they saw a party of about 200 Blackfeet on the river bank, motioning to them to come ashore. Potts, instead of surrendering his gun peaceably, shot and killed one of the Indians, and immediately died under a shower of arrows.