Quoted in The Big Beat: Conversations with Rock's Great Drummers (Levon) ↑

When D. J. Fontana came in

It’s always been that the rockabilly stuff was real bouncy, driving fours on the bass drum, almost like a jazz feel at times. Circling, just continuously circling. But when D.J. [Fontana, drummer for Elvis Presley] came in, all of a sudden he would plant that thing down and he would start stacking verses against each other with his fills, building up to the solos, and riding the solos in and riding them out. It was great because D.J. gave the music some foundation, some architecture.

Levon Helm, as quoted in The Big Beat: Conversations with Rock’s Great Drummers