In the music of composers of early 20th century France, fourth chords became consolidated with ninth chords, the whole tone scale, the pentatonic scale, and polytonality as part of their language, and quartal harmony became an important means of expression in music by Debussy, Maurice Ravel, and others. Examples are found in Debussy's orchestral work "La Mer" (The Sea) and in his piano works, in particular "La cathédrale engloutie" (The Sunken Cathedral) from his "Préludes" for piano, "Pour les quartes" (For Fourths) and "Pour les arpéges composées" (For Composite Arpeggios) from his "Etudes".