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

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."