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Historical Background

Dilemma at the mouth of the Marias

Lewis and Clark faced their first major navigational test and primary crucial decision. They needed to decide and decide correctly which fork was the Missouri, the river that would lead them to the Rockies, the Shoshonis, and horses. Two months of the travel season had already elapsed. If the wrong branch were followed, the loss of time in retracing their steps and returning to the other would dampen morale, deplete supplies, and undoubtedly prevent crossing the Rockies before winter set in. As a result, the Pacific could not be reached that year, and an ignominious retreat to St. Louis would likely be necessary. Worst of all, though the commanders did not know it at the time, if they had gone up the northwestern stream they would probably have eventually encountered hostile Blackfeet—with possibly calamitous results.

The information the Minitaris had provided the two captains, some of which they had misinterpreted or misunderstood, puzzled them. It did not place a key river flowing in from the north at this point. Unfortunately, on May 8 they had incorrectly determined that the Milk River was the "River That Scolds All the Others" that the Indians had described. Now what stream was the northwestern one? Or did the southwestern one flow into the northwestern?

Complicating the problem, the northwestern branch, gorged by spring runoff from the mountains, was much bigger than normal. And it had the same muddy color as the Missouri so far. The sparklingly clear southwestern fork, larger and with a faster current, passed over a rocky bed. Although the captains early surmised that the southwestern fork was the Missouri, the final decision was to take about a week.

Modern junction of the Marias and Missouri, looking downstream and to the east. The former enters from the left center. In the foreground, is the narrower of the two Missouri channels in the area; the main channel runs on the far side of the island in the center of the picture. In 1804-6 the Marias ran closer to the bluff line, and the confluence of the two rivers was about 2-1/2 miles downstream. (National Park Service (Appleman, 1964).)

Between June 4 and 8, Lewis and a party reconnoitered overland about 60 miles up the northwest branch (Marias). [101] On this trip, Lewis and Windsor almost fell off a precipice; the former was saved by his espontoon, which he usually carried when walking. Meantime, on June 4-6, Clark and another overland group explored the southwestern branch (Missouri) about 13 miles upriver to the site of present Fort Benton, Mont., then traveled northwestward to an upstream point on the Teton River. From a ridge, they could see that the branch ran southwestward for a long stretch. [102] They turned back to camp.

Comparing notes, reevaluating the Minitari data, and utilizing maps they had brought from St. Louis, Lewis and Clark finally agreed beyond a doubt that the southwestern branch was the Missouri—though all the other men held the opposite to be true. The bigger southwestern stream ran in the expected direction, its current was swifter, and its clearness and rocky beds indicated that nearby mountains fed it. Because of the turbid nature and muddy bed of the northwestern fork, the leaders judged that it probably either did not penetrate the mountains or upon leaving them traveled a long distance over the plains. Lewis and Clark decided that this fork rose east of the Rockies and south of the Saskatchewan, the British river to which they oriented so many of their geographical judgments.

Packs of timber, or lobo, wolves were encountered at the confluence of the Judith and Missouri Rivers and at the Great Fails of the Missouri. Today, this predatorial species faces extinction. (Bureau of Sport Fisheries and Wildlife (Don Reilly).)

Not to be outdone by Clark's naming of the Judith, Lewis called the stream flowing in from the northwest "Maria's River" after Maria Wood, a cousin in Virginia. It was noble enough, though he felt that its troubled waters poorly comported with the "pure celestial virtues and amiable qualifications of that lovely fair one."