Downward motion will characterise structural endings, and, as a corollary, upward motion will occur before the descents-~either at the beginning or in the middle of melodic lines. The tonal system, however, through the phenomenon of octave equivalency, provides an escape clause from these constraints of the structural background. Prolongations, in widening the field for tonal activity, will also free the upper voice from the need for uniformly descending resolutions of linear tension. (331)
The examples from Verdi and Schubert show registral repositioning upward of individual tones in a descending urlinie: the ^3 in the middle of a five-line, and the final ^1, respectively. In both cases, the repositioning is associated with figures in the text.
With respect to the structural cadence of Schubert's "Die junge Nonne" -- and therefore the Urlinie shape -- Schachter has simply gotten it wrong. His graph shows bars 52-61; these include a "cadence [that] achieves its rise to the tonic through a brief stepwise line that culminates in the notes C-D-E-F; F of course is the tonic note and E, the leading tone, can be understood as an inner-voice note of V that substitutes for ^2" (333). This is not the structural cadence -- "a variant of this same cadence" has that role: mm. 74-83. These latter measures are shown in the graphic below, with Schachter's reading mapped onto them: ^5 with inner voices ^3 and ^1 below, the structural bass elements IV-V-I and ^4-^3 (moving from voice to piano)-^2-^1 with accompanying sixths below, two lines moving up in the voice: ^3-^5, then ^5-^8.
Against that I offer my reading below. The ^5 over ^1 is clear at the outset. Note the string of unstable harmonies with parallel octaves between voice and bass at the same time the voice repeatedly outlines the octave register (C4-C5, D4-D5, F4-F5). The octave, and the space of the octave, are obviously crucial here. The clue, I think, is in the "bell sounds" -- the piano left hand crossover pitches, F5 in m. 74, C5 in m. 75, etc., The voice duplicates the piano's notes each time she reaches the word "Getön" (meaning the bell sound): the link between "Getön" on F5 and "Höh[e]n" on F5 is obvious. The piano may have to work the mundane task of the cliché cadence, but the voice has been transported -- and that, I would assert, is what this song is all about.
In the MTS article, I wrote about the Pietist concept of Jesussehnsucht (longing for Jesus) in connection with the funerary chorale "Christus, der ist mein Leben." Here it is not an expression derived from the Protestant notion of personal salvation, but from the Catholic tradition of specifically female figures (usually nuns) yearning for the "heavenly marriage" with Christ. That has been merged with simple Romantic nature imagery -- in the first verse, she speaks of her fear at a stormy night; in the second verse, the emotion is the turbulence of her yearning for Christ (at the end of this, she calls out for the himmlischer Bräutigam); in the final verse, the bell sound seems to clear and calm the air, and she can speak of peace, desire, and heaven.
Schubert obliges with a ballad style and textures and affects that remind one of Erlkönig. The first two verses are in F minor, with obsessive emphasis on C5 and Db5 in the voice (see below); the final verse is in F major.
I am hardly finished with the striking features of this song. Contrary to the suggestion in the lines that Schachter quotes, with their "sweet sound" and "eternal heights," the harmonic progressions of the F major verse remain surprisingly tense (at least, unstable) right up to the structural cadence -- it is the release in that final rising gesture, going one last time to F5, that enables the harmony to come to peace itself. Some sections of the song look very amenable to transformational readings, and the incessant right hand tremolos reveal a different version of the Riemannian hand. Perhaps I'll follow up those leads some other day.