It has been altered. It may have once been a regular side button skirt with a waist band or maybe even a dress but the waist was turned over and elastic was tunneled in, making this easy to wear but you would need an over bloused top or a belt.
It's poly chiffon in two layers, the top layer dances nicely! The underskirt is not as voluminous. The waistband was not done very well but it really doesn't show on the outside when you wear a belt or a top that goes over it. That's the only flaw.

If you like being "Fashion-Obtuse", check out the styling with the white tee shirt...

MEASUREMENTS
waist unstretched is 34'"
hip on underskirt goes to 46"
length 31"

This item is sold from an excellent, highly rated vintage boutique in Northfield, OH.