The first rock and roll song?

[FOFGuyAKAPerson]

So I've been into the early rock, and by early, I mean like 50's rock. I've been trying to find the earliest rock and roll song, out of boredom. I was wondering what some of you guys think.

The hard part about finding the earliest rock and roll song is the definition of "rock and roll". Different genres kind of just evolved into rock and roll. In my opinion, these songs would be examples of rock and roll songs:
http://www.youtube.com/watch?v=F13JNjpNW6c Tutti Frutti by Little Richard
http://www.youtube.com/watch?v=-mZLpDuuf40 (We're Gonna) Rock Around The Clock by Bill Haley And His Comets
http://www.youtube.com/watch?v=eWNykOk2ckE Johnny B. Goode by Chuck Berry

So what's your opinion? If you guys don't know any early rock and roll songs, I can post some and you can choose.
In my opinion, this is the first one:
http://www.youtube.com/watch?v=uxHQUvCkV20 That's All Right by Arthur Crudup (The Beatles, Elvis, and bunch of people covered this)