On the afternoon of April 7, 1805, winter quarters were abandoned. Of the original forty-five men two had been lost; but three recruits had been gained, Chaboneau, his squaw Sacajawea, and their infant son, born in February. From Fort Mandan fourteen of the men returned to St. Louis in the barge, carrying documents, collections, and trophies, while thirty-two went onward, to be separated from their kind for almost eighteen months. On this day Captain Lewis wrote in his journal:

“This little fleet altho’ not quite so rispectable as those of Columbus or Capt. Cook, were still viewed by us with as much pleasure as those deservedly famed adventurers ever beheld theirs; and I dare say with quite as much anxiety for their safety and preservation. We were now about to penetrate a country at least two thousand miles in width, on which the foot of civilized man had never trodden; the good or evil it had in store for us was for experiment yet to determine, and these little vessells contained every article by which we were to expect to subsist or defend ourselves. However as the state of mind in which we are, generally gives the coloring to events, when the imagination is suffered to wander into futurity, the picture which now presented itself to me was a most pleasing one, entertaining as I do the most confident hope of succeeding in a voyage which had formed a darling project of mine for the last ten years, I could but esteem this moment of our departure as among the most happy of my life.”

April 26th they came to the mouth of the Yellowstone River, which enters the Missouri 1888 miles above St. Louis. They had had no adventure of moment; neither was there cause for immediate anxiety, save as they observed signs of the Assiniboins. From the tribes with whom they had talked at winter quarters, they had heard stirring tales of this cut-throat band, which had inspired the wish to pass unobserved through their country. This desire was fulfilled. There was no meeting with the Assiniboins.

Of all the wild creatures of the Western wilderness, the one which could least be spared from the literature of adventure is the grizzly bear. Lewis and Clark were the first white men to give an account of this beast. Many of the Indian lodge-tales to which they had listened rang with the fame of the grizzly, as a background for the greater fame of the narrators. As a matter of course, fact and figment were inextricably blended in these tales; but, while they did not show the animal as it was, they could not exaggerate its untamable courage, its ferocity, or its rugged power of endurance. On April 29th, Captain Lewis, with a party of hunters, proved the truth of all that had been told him upon these points, and more; and upon many occasions thereafter, while the party was making its way from the Yellowstone country to the mountains, there were encounters from which the men escaped by mere good fortune. The most critical adventures with the Indians were but child’s play in comparison. Despite their boasting, the Indians would seldom venture to provoke a fight with a grizzly, except in the most favorable circumstances, and when strength of numbers inspired them with bravado. Reckless and headlong as wild elephants, nothing would daunt the grizzlies, once they had set about fighting; and so hardy were they as often to escape, apparently unharmed, though their vital parts were riddled with lead.

Until the Rocky Mountains were reached, there was almost no hardship arising from scarcity of food. Early in May, Captain Lewis wrote that game of all sorts abounded, being so gentle as to take no alarm of the hunters. “The male buffalo particularly will hardly give way to us, and as we approach will merely look at us for a moment, as something new, and then quietly resume their feeding.... Game is in such plenty that it has become a mere amusement to supply the party with provisions.” In the months that followed, the men carried a blessed memory of that abundance.

As they drew near to the foothills, navigation became more and more difficult. The river lost the sullen, muddy aspect of its lower course, where it flowed between low, sandy banks, and took the character of a mountain stream, walled with rock and filled with dangers. Then it was that the cottonwood skiffs betrayed their weaknesses. Accidents were of almost daily occurrence; and on one occasion the boat containing the instruments and papers was nearly lost. They were then more than two thousand miles from any place where such a loss could have been repaired. To go on would have been idle, without means for making accurate observations; they would have been obliged to turn back. In the face of this perpetual threat, they had no resource but to take their chances with luck; with the best they could do, they could not adequately safeguard themselves against calamity. For the time being, at least, they were rank fatalists.

On Sunday, May 26th, Captain Lewis left camp on foot, ascended to the summit of a ridge of hills near the river, and from the height had his first glimpse of the distant ranges of the Rocky Mountains. This was about a year and a half before Pike’s discovery. The journal entry for that day comes near to showing emotion:

“While I viewed these mountains I felt a secret pleasure in thus finding myself so near the head of the hitherto conceived boundless Missouri; but when I reflected on the difficulties which this snowey barrier would most probably throw in my way to the Pacific, and the sufferings and hardships of myself and party in them, it in some measure counterballanced the joy I had felt in the first moments in which I gazed on them; but as I have always held it a crime to anticipate evils I will believe it a good comfortable road until I am compelled to believe differently.”

Progress grew increasingly hard. Rapids were numerous, over which the boats could not be urged with oars; so the men were compelled to walk upon the banks, drawing the craft with tow-lines. These lines were made mostly of elk-skin, which became softened and rotted by the water and often broke under the strain, causing many accidents of a trying and serious nature. The banks were sometimes so rocky and precipitous as to afford no foothold; then the men took to the water, wading, swimming, making headway as they could. One extract from the journals will illustrate the severity of their toil:

“May 31st [a rainy day]. Obstructions continue, and fatigue the men excessively. The banks are so slippery in some places, and the mud so adhesive, that they are unable to wear their moccasins; one fourth of the time they are obliged to be up to their arm-pits in the cold water, and sometimes they walk for several hours over the sharp fragments of rocks which have fallen from the hills. All this, added to the burden of dragging the heavy canoes, is very painful; yet the men bear it with great patience and good humour.”

On June 3d they came to a point where the river forked; and here, as the forks were of nearly equal volume, they were in doubt as to their route. Captain Lewis wrote:

“On our right decision much of the fate of the expedition depends; since if, after ascending to the Rocky Mountains or beyond them, we should find that the river we were following did not come near the Columbia, and be obliged to return, we should not only be losing the traveling season, two months of which have already elapsed, but probably dishearten the men so much as to induce them either to abandon the enterprise, or yield us a cold obedience, instead of the warm and zealous support which they have hitherto afforded us.... The fatigues of the last few days have occasioned some falling off in the appearance of the men; who, not having been able to wear their moccasins, have had their feet much bruised and mangled in passing over the stones and rough ground. They are, however, perfectly cheerful, and have an undiminished ardor for the expedition.”

In order to settle the doubt, the officers took each one branch of the stream and proceeded to explore it for some distance above the confluence, to determine its direction. Captain Lewis, ascending the northern fork, became convinced that it was not the main stream; and to it he gave the name, which it still bears, of Maria’s River. His warmth of youth speaks in this paragraph:

“I determined to give it a name and in honour of Miss Maria W d [Maria Wood, his cousin] called it Maria’s River. It is true that the hue of the waters of this turbulent and troubled stream but illy comport with the pure celestial virtues and amiable qualifications of that lovely fair one; but on the other hand it is a noble river; one destined to become in my opinion an object of contention between the two great powers of America and Great Britin, with rispect to the adjustment of the North westwardly boundary of the former; and that it will become one of the most interesting branches of the Missouri.”

Meanwhile, Captain Clark had gone far enough along the southern fork to satisfy himself that that was the proper course; and when he rejoined Captain Lewis at the confluence, preparations were made for continuing the journey. It was then clear that the burdens of the men must be lightened; accordingly, considerable quantities of merchandise, ammunition, etc., were buried in the earth, or “cached,” after a method often followed by travelers of the West; care being taken to preserve the stores against moisture. One of the periogues also was left at this place, securely hidden.

While this work was going on, Captain Lewis, with several of the men, proceeded to explore the southern stream more minutely, seeking to devise means for passing the canyon at the mouth of which the party was encamped. June 13th he heard in the distance the roar of the Great Falls of the Missouri; and, after pushing on for several miles, he stood at the foot of the lower cascade. Relying upon descriptions which had been given by the Indians at the Mandan villages, he now felt assured that the right way had been chosen.

He seated himself before the roaring sheet of water, and endeavored to put a description of it upon paper; but then he added helplessly:

“After wrighting this imperfect description I again viewed the falls and was so much disgusted with the imperfect idea which it conveyed of the scene that I determined to draw my pen across it and begin agin, but then reflected that I could not perhaps succeed better than penning the first impressions of the mind; I wished for the pencil of a Salvator Rosa, or the pen of a Thompson, that I might be enabled to give to the enlightened world some just idea of this truly magnificent and sublimely grand object, which has from the commencement of time been concealed from the view of civilized man; but this was fruitless and vain. I most sincerely regreted that I had not brought a chimeeobscura with me by the assistance of which I could have hoped to have done better but alas this was also out of my reach; I therefore, with my pen only endeavored to trace some of the stronger features of this seen by the assistance of which and my recollection aided by some able pencil I hope still to give to the world some fain idea of an object which at this moment fills me with such pleasure and astonishment.”

On the next day he went ahead, alone, and discovered that this was but the first of a long series of cascades, extending for many miles up the canyon. It was a day of excitement. While returning to rejoin his party, he suffered his gun to remain for a time unloaded; in this plight he was surprised by a grizzly bear. Cut off from any other retreat, he was forced to take to the water, in which he stood to the depth of his armpits, facing the brute upon the bank and preparing to defend himself in a hand-to-hand struggle; but, in a manner wholly out of keeping with his family traditions, the grizzly was content to walk away without attacking. Proceeding about nightfall, the young officer encountered a strange beast, probably a wolverine, which showed fight; and a little later he was charged by three bulls from a herd of buffalo. Upon waking the next morning, he found a large rattlesnake coiled about the trunk of the tree beneath which he had slept.