Structural level

It may be conceived of in a specific piece as the opening in the tonic and the return to the tonic with a perfect authentic cadence (V-I) after the development of sonata allegro form.

Strata is the translation given by John Rothgeb for Schichten ("Levels") as described by Oswald Jonas in his Introduction to the Theory of Heinrich Schenker.

"[5] The image hereby shows Schenker's earliest presentation of levels in a figure, his analysis of J.S.

Schenker writes: "The figure hereafter shows the gradual growth of the voice-leading prolongations, all predetermined in the womb of the Urlinie.

f) finally shows the removal of the consecutive fifths by means of the exchange 6–5, which is also welcome to the diminution.