Samuel L. Clemens and Richard Burton both took a steamboat from St. Louis to St. Joseph and neither had much to say about the trip. Burton does address the physical characteristics of the Mississippi River drainage basin and presents arguments as to why the Missouri River should not be considered as the Mississippi's headwaters.
St. Louis to St. Joseph - 1861: Day By Day
July 18 Thursday – Orion and Sam left St. Louis on the Sioux City for St. Joseph, Missouri [MTL 1: 122 citing Mollie Clemens’ Journal]. In Roughing It, Sam wrote:
“— a trip that was so dull, and sleepy, and eventless, that it has left no more impression on my memory than if its duration had been six minutes…”
A. Hoffman gives this date as July 10, 1861 [62]. July 18 seems more likely.