Historic Diaries: Marsh, 1834
Aboard the Steamboat Winnebago
Dr. Emerson: John Emerson (1801-1843) was the Army's assistant surgeon at Fort Armstrong. He enlisted from Pennsylvania and had arrived at Rock Island only a few months before Marsh passed through. He brought with him a slave -- the celebrated Dred Scott, who would later claim (unsuccessfully) that he was a free American because he had lived with Dr. Emerson for several years in free states. Marsh makes no mention of Scott in his diary.
The Winnebago: At this time, about 35 steamboats were plying the Upper Mississippi and its tributaries; in 1834 one arrived at Galena, for example, about three times a week, on average (Peterson, William J. Steamboating on the Upper Mississippi [Iowa City: 1937]). In 1832 the Winnebago had carried Black Hawk away from his homeland in chains, a trip recorded in his autobiography and in this memoir by John Shaw, who was also on the Winnebago for part of the voyage.
"promiscuous company": Peterson records that "Among the deck passengers games of chance, coarse jokes, fishing, and often drunkienness prevailed. Robberies were frequent. In 1833 some thieves carried away almost every piece of wearing apparel they could infd belonging to the passengers on the Winnebago." 
Yellow Banks: A spot about 50 miles down the Mississippi, on the east (Illinois) bank, where the Sauk and Fox often came to trade. Upper Yellow Banks is today called New Boston; Middle Yellow Banks is Kiethsburg, Ill.; and Lower Yellow Banks, which the Indians called Oquawkiek, is today Oquawka, Ill. Map.
2d [July 1834] Wed.
Called on Dr. Emerson at his quarters. This gentleman treated me very politely indeed... While conversing upon the subject of religion with a son of Mr. D[avenport], a man came informing me that the Steam Boat was near - Immediately my luggage was carried to the bank of the river. I hailed the boat, The Winnebago, she came to and so I went on board.
Here I find a promiscuous company have met, with one professor of the Pres[byterian] Ch belonging to Missouri, and others are card-players. Met also with a Mr. Lockwood, brother of Judge L. at Prairie du C. His present place of residence the De Bukes [Dubuque] Mines on the Miss[issippi].
Arrived at the Lower Yellow Banks between 8 & 9 o'clock in the eve., and there met with Dr. Williamson. Took up lodgings at Mr. S. Phelps, an Indian trader, who treated us with great hospitality.