Late 1930's Wedding Gown

From the seller:
  •Period : Authentic Original Vintage : circa 1920s 
 •Style : Woman Wedding Bridal Dress 
 •Maker : Custom-Made for a Parisian Socialite : made in France
 •Fabric : 100 % Silk : Luxurious Heavy Cashmere Soft Satiny Silk 
 •Color : Pearly White 
 •Details : Glamorous Mermaid Style - Pleats Accents - Side Closure - Attached Belt - Floor Length 
 • Pre-Loved Condition : Good Condition : worn once : please read details below
 • Detailed Condition : 1 small hole ( 10 x 5 mm ) on the side near the hem
 • Woman Size : Medium ( please check the measurements below before bidding )
 •Waist : 29 • Bust ( armpit to armpit ) : 17.5 inches 
 •Shoulders ( seam to seam across back ) : 15.5 inches
 •Sleeves : 25 inches •Front Height ( shoulder seam to front bottom ) : 54 inches

 From Me:

http://vintagepatterns.wikia.com/wiki/McCall_9689

The pattern above is from 1938.  The dress is just an elongated version of this style.