From the seller:
Unusual cut and layering on this romantic white silk chiffon and silk lace flapper dress dating to the 1920s. Lace cap sleeves with the same lace at dropped waist an in a draped layer in the skirting, layers of the chiffon in the skirt. In overall good vintage condition delicate but not dry with age/storage yellowing.
Measurements: 42" chest straight down to hips, 46" total length.
Although the dropped neckline is nothing new, the way the skirt is cut is pretty unique. The bias cut with the curved addition is something that is seen in the late 1920's, however.
Past Patterns actually has a pattern for a late 1920's dress (1927) that has similar detailing in the top to the skirt of this dress.