It seems the consensus is that the lynch-pin or the pivot between ragtime and jazz is Jelly Roll Morton. A piano player that hailed from New Orleans around 1880, he was in the thick of the action concerning the "birth" of jazz. He seems to have been quite a character. He even pronounced, most audaciously, that he actually invented jazz. This of course seems a little far fetched but he is highly regarded as the first jazz composer - the first one to get it down on the record. He wouldn't record his first music until the 1920's, however, he was a person who was instrumental in spreading the music across the States, once he left New Orleans around 1907 or so.
His music proved to be highly influential especially when jazz later developed in the 20s and 30s. I have chosen 12 songs to introduce myself to his music.
Black Bottom Stomp
Buddy Bolden's Blues
Deep Creek Blues
Original Jelly Roll Blues
Doctor Jazz Stomp
Jelly Roll Blues
King Porter Stomp
You can hear the heavy blues influence in Jelly Roll's playing. You can't help but listen to his rolling piano style and think of later piano heroes like Fats Domino and Jerry Lee Lewis. You can also picture how his new brand of music would have been received in the sporting houses of Storyville in the early part of the century. This was music that people could dance to - and break away from the shackles that the Victorian era had put on society. This was new music for a new century.
In my research of Jelly Roll I was delighted to discover that he left behind a huge volume of work in the form of the Library of Congress recordings, made by Alan Lomax. I have heard clips of him reminiscing about his early playing days in New Orleans and the music that he wrote. I am eagerly looking forward to getting my hands on all 8 CDs and will post my reactions here.