Black Embroidered Cotton Costume Dress circa 1920s

An unusual 1920s (?) black cotton dress or costume. Snaps up opening toward front neck, peaked sleeves with coral pink embroidery. Small matching piece that I thought at first was a little caplet to cover shoulders but while the neckline (?) fits the neck, the shoulders are too narrow. Double layered with matching embroidery. I show it perched on the shoulder folded in half. I wish I knew what it is! A cool "set" to play with, however. No holes or stains. 

Measures

46" bust, 50" waist, 54" hips, 42" long, 20" sleeves