This discussion is close to my heart. For some years I've been trying to isolate reliable sources of genuine 19th and early 20th century African American secular songs.

Books are about all we've got. In general it's best to stay away from those printed after about 1945, as they tend to suffer from "version creep" due to the Folk Scare. It should be emphasized over and over again that the best printed primary sources are the earliest. (I.e. not Burl Ives, though "Buckeye Jim," descended from a New Orleans roustabout song, is an example of something good in his collection.)

Some of the following works have been cited above in scattered references, but it helps to pull them together as a working collection. These are outstanding, the best:

Odum and Johnson, Negro Workaday Songs
Odum and Johnson, The Negro and His Songs
Scarborough, Dorothy, On the Trail of Negro Folk Songs
Newman I. White, American Negro Folk Songs
Wolfe, Charles, Thomas W. Talley's Negro Folk Rhymes

These further collections focus on spirituals but have some secular songs and they're good early versions:

Allen William Francis et al, Slave Songs of the United States
Parrish, Lydia, Slave Songs of the Georgia Sea Islands
Work, John C., American Negro Songs and Spirituals

General collections with much good Afro-American secular material are:

Lomax, John A and Alan, American Folk Songs and Ballads
Lomax, John A and Alan, Our Singing Country
Sandburg, Carl, American Songbag

Later Lomax collections should be avoided because of Alan Lomax's unfortunate habit of collating, rearranging and now and then recomposing material, but the above two books are fairly sound.

A great collection of largely Afro-American roustabout songs is:

Eddy, Mary O., Steamboatin' Days.

All these books are more or less hard to find, but copies may be available on Amazon-used, Abe or Alibris.

Take a look at any collections of minstrel songs you can find. Particularly in the early (1830s-1850s) history of minstrel shows in America, so far as we can tell at this late date, a number of genuine traditional Afro-American songs were used on stage. Though the degree of composition by such early performers will always be at issue (and Dan Emmett in particular composed a lot of his own material), songs like "Juba," "My Old Dad," "Jaw Bone," "Turkey Buzzard," "Clare De Kitchen," "Johnny Boker," Sally Is Your Hoecake Done," "Shew Fly," "Take Your Foot Out The Mud" and maybe "Boatman's Dance" seem to show folk origins.

Lastly, beware of recorded versions! Relatively little on record is true to the older styles. But a few songsters like Henry Thomas, Elizabeth Cotten and Blind Willie McTell (and even Leadbelly) have a few choice songs each.

On the other hand, the best modern groups like Martin, Bogan and Armstrong and Joe and Odell Thompson had a great feel for older material and are worth a hearing.

And always check the Library of Congress and other field recording collections for the Afro-American songs and music they have made available.

When you cover this much ground, you realize there are hundreds, perhaps thousands of excellent early Afro-American traditional songs out there in more or less authentic form. They turn up in strange places, like the songs Joel Chandler Harris included in two of his Uncle Remus books, some obviously his poetry, but a few sounding reasonably genuine.

Enjoy!

Bob