Songs from this period had many different structures. A testimony of those times can be found for instance in Henry Thomas's recordings. However, the twelve-, eight-bar, or sixteen-bar structure based on tonic, subdominant and dominant chords became the most common. Melodically, blues music is marked by the use of the lowered third and dominant seventh (so-called blue notes) of the associated major scale. The standard 12-bar blues form is noted in uncorroborated oral histories as appearing communities throughout the region along the lower Mississippi River during the decade of the 1900s (and performed in New Orleans at least since 1908). One of these early sites of blues evolution was along Beale Street in Memphis, Tennessee. However, author Eileen Southern has pointed out several contrasting statements by old-time musicians. She cites Eubie Blake as saying "Blues in Baltimore? Why, Baltimore is the blues!" and Bunk Johnson as claiming that the blues was around in his childhood, in the 1880s.