Her terse article in thepeerage is here.
From Paul Frecker; size increased by half and sepia tone removed by gogm (and re-added tp border only with Photoshop) by gogm.
Lady Anne wears a crinoline dress with a high neck under-garment under a square neck bodice. Her dress also has large pagoda sleeves. She appears to be wearing a cone crinoline.
Keywords: 1861, Silvy, Anne Aldercron Milliken-Napier, Aldercron family, Milliken-Napier family, British, straight coiffure, high neckline, collar, square neckline, ruff, pagoda sleeves, under-sleeves, cuffs, crinoline, pin