From The Life of Mark Twain: The Early Years, 1835-1871, page 84

October,  early – Sam walked along the main street of Keokuk in swirling snow, and found a fifty-dollar bill. Astounded, he later recounted, “It  was a fifty-dollar bill—the only one I had ever seen, and the largest assemblage of money I had ever seen in one spot” [Powers, Dangerous 243]. He  advertised it but after five days with no claimant he felt he’d done enough:

“By and by I couldn’t stand it any longer. My  conscience had gotten all that was coming to it. I felt that I must take that  money out of danger” [MTB 111].

October  13 Monday – Sam made a brief stay in St. Louis, staying with his mother,  and sister. He attended the St. Louis Agricultural and Mechanical  Association Fair. He wrote a sketch of it,  titled “The Great Fair at St. Louis,” signed, “SAM,” which appeared in the  Keokuk Post on Oct. 21 and then in the Saturday Post on Oct. 25 [MTL 1: 69].
 

October  18 Saturday – Still in St. Louis, Sam wrote the first Thomas  Jefferson Snodgrass letter, burlesquing Shakespeare’s Julius  Caesar [Gribben 626]. Sam used  dialect, and grammatical and spelling errors to characterize a country bumpkin  getting the worst of it in the big city. It was a literary strategy that would  come to fruition in many of his future works. Snodgrass was also the last pen  name Sam used prior to Mark Twain, in Nevada, Feb. 1863.

October  19 Sunday – Sam arrived in Keokuk, Iowa (see Oct. 18 entry).

October  21 Tuesday – “The  Great Fair at St. Louis,” signed, “SAM,” appeared in the Keokuk Post [ET&S 1: 378].

October  22 Wednesday ca. – Sam traveled by river packet to Quincy, Illinois [MTL 1: 70].

October  23 to 24 Friday –Sam traveled by train to Chicago and Indianapolis to Cincinnati [MTL 1: 70].  Branch gives on or  about Oct. 24 as the date Sam arrived in Cincinnati [Branch, “Bixby” 2].

October,  late – In Cincinnati Sam found employment as a typesetter for T.  Wrightson and Co., one of the city’s  leading printers. He worked there into the next spring, some six months [MTL 1: 70]. Sam’s time in Cincinnati is  one of the “least documented of his life…” [MT Encyclopedia, Poole 145] but  he did write two more Snodgrass letters while there. Sam lived in a  boarding house. Long hours at work plus discussions with other boarders didn’t  allow Sam much time for writing.

November  1 Saturday – Sam’s first Snodgrass letter dated Oct. 18from  St. Louis titled, CORRESPONDENCE  ran in the Keokuk Saturday Post.

November 14 Friday – Sam dated his second Snodgrass   letter from Cincinnati [MT Encyclopedia, Abshire 694].

November  18 Tuesday – An  untitled sketch, dated Nov. 8 and signed “L,” about a Cincinnati boarding house ran in the Keokuk Post.  It is attributed to Clemens [ET&S 1: 382; MTL 1:  70]. Britton examines the piece and makes a case for it being Sam’s, and  Mcfarlane being autobiographical rather than fictitious [16- 17]. Note: Britton mistakenly  writes the sketch was published on Nov. 8, but it was dated Nov 8   and published Nov. 18.

November  29 Saturday – The second Snodgrass letter dated Nov. 14, SNODGRASS’ RIDE ON THE RAILROAD ran in the  Keokuk Post [MT Encyclopedia, Abshire 694; Camfield, bibliog.].

November 30 Sunday – Sam’s 21  birthday.

December  6 Saturday – Sam’ second Snodgrass letter ran again in the  Keokuk Saturday Post [Schmidt].

January – On Dec. 29, 1905 Sam  answered a question from an unidentified person:

“Yes I did lay aside the ‘stick’ to resume  it no more forever; but January 1857 was the time it happened, & Keokuk,  Iowa the place” [MTP]. Note: the “stick” was the typesetter’s line of  type. Sam soon after began his steam boat career.
 

January 23 Friday – In Keokuk, Henry Clemens wrote to Sam.

Your letters seem to be very strongly afflicted  with a lying-in-the-pocket propensity; for no sooner had I read your last, but  one, than it was consigned to one of the pockets of my overcoat, from whose  “vasty depths” I have but this moment fished it up, to answer it.

February  16 Monday – Sam boarded the packet Paul Jones (353 tons), on its way from Pittsburgh, for passage to New  Orleans, commanded by  Hiram K. Hazlett and piloted by Horace E. Bixby (1826-1912), and Jerry Mason [Branch,  “Bixby” 2]. Branch presents evidence for this date over Apr. 15.