Question: What man is credited with helping Dan Emmett write the song which has become a toponym for the Southern United States?

Context paragraphs:
List of foods of the Southern United States: This is a list of foods of the Southern United States.  The cuisine of the Southern United States is defined as the historical regional culinary form of states in the Southern United States.  Southern cuisine has many various dishes and foods.

History of the Southern United States: The history of the Southern United States reaches back hundreds of years and includes the Mississippian people, well known for their mound building.  European history in the region began in the very earliest days of the exploration and colonization of North America.  Spain, France, and England eventually explored and claimed parts of what is now the Southern United States, and the cultural influences of each can still be seen in the region today.  In the centuries since, the history of the Southern United States has recorded a large number of important events, including the American Revolution, the American Civil War, the ending of slavery, and the American Civil Rights Movement.

Seely Simpkins Jig: "Seely Simpkins Jig" is a song by American songwriter Dan Emmett.  Emmett named the song for Seeley Simpkins, a resident of Knox County, Ohio, well known for his fiddle playing and whistling.  Simpkins' property neighbored that of Thomas Snowden, a man whom Howard L. and Judith Sacks credit with helping Emmett write the song "Dixie".  "Seely Simpkins Jig" was later published as a quickstep in "Fife Instructor", a manual by Emmett.

The Boatman's Dance: The Boatman's Dance is a minstrel song credited to Dan Emmett in 1843 and arranged by Aaron Copland as part of his set of "Old American Songs".

Southern Agrarians: The Southern Agrarians (also the Twelve Southerners, the Vanderbilt Agrarians, the Nashville Agrarians, the Tennessee Agrarians, and the Fugitive Agrarians) were a group of twelve American writers, poets, essayists, and novelists, all with roots in the Southern United States, who united to write a pro–Southern agrarian manifesto, published as the essay collection "I’ll Take My Stand: The South and the Agrarian Tradition" (1930).  The Southern Agrarians greatly contributed to the Southern Renaissance, the revival of Southern literature in the 1920s and 1930s, and were based at Vanderbilt University, in Nashville, with John Crowe Ransom as the unofficial leader.

Dixie (song): "Dixie," also known as "Dixie's Land," "I Wish I Was in Dixie," and other titles, is a popular American song.  It is one of the most distinctively American musical products of the 19th century, and probably the best-known song to have come out of blackface minstrelsy.  Although not a folk song at its creation, "Dixie" has since entered the American folk vernacular.  The song likely cemented the word "Dixie" in the American vocabulary as a toponym for the Southern United States.

Jordan Is a Hard Road to Travel: Jordan Is a Hard Road to Travel is a song composed by American songwriter Dan Emmett for an 1853 blackface minstrel show.  The song became extremely popular throughout the United States.  It was recorded in 1927 by banjo player and singing entertainer Uncle Dave Macon, an early Grand Old Opry star.  The song was later included on the Smithsonian Institution's Folkways collection, "".

Johnny Roach: "Johnny Roach" is an American song written by blackface minstrel composer Dan Emmett.  The song was first published in 1859.  The lyrics tell of a slave who has escaped to the Northern United States.  He laments his lost plantation house and realizes that he really belongs in the South:

Emmett, West Virginia: Emmett is an unincorporated community in Logan County, West Virginia, United States.  Emmett is located on Elk Creek, County Route 11/1, and the CSX Railroad 4.8 mi southeast of Man.  Emmett had a post office, which closed on March 7, 1998.

Southern States Art League: The Southern States Art League, originally called the All-Southern Art Association, was formed in the 1920s to draw attention to artists from the southern United States.  A number of its early members were closely associated with the Charleston Renaissance, and it has been credited with helping to establish the South as "a viable art center and formidable force in the realm of American culture."

Supporting paragraphs: Seely Simpkins Jig Dixie (song)
Answer: Thomas Snowden