From damesalamode.tumblr.com/post.
This equestrian dress blends a flounced pouffy skirt with a vest and waist band under a military style jacket. This rider would be forced to doff her hat to ride quickly. She appears to be wearing a chatelaine.
Keywords: 1787, French, high straight coiffure, floral ribboned hat, chemise, high neckline, neckline ruff, long under-sleeves, ruffles, fichu, jacket, lapels, epaulettes, elbow length close over-sleeves, buttons, cuffs, vest, waist band, vee waistline, full skirt, maxi-length skirt, flounces, chatelaine, gloves, shoes