From findagrave.com/memorial/13869450/charlotte-frances_frederica-spencer; enlarged by one quarter and increased contrast.
The size of Charlotte's bustle leads me to believe this is from the middle of the 1880s.
Keywords: Charlotte Countess Spencer, Charlotte Frances Frederica Seymour, Seymour family, Spencer family, Countess, British, wavy coiffure, earrings, necklace, fichu, vee neckline, bodice, U-décolletage, floral bodice ornament, buttons, long tight sleeves, bracelets, bustle, tight under-skirt