Unusual Gown CDV

What a dress! This is definitely attention-getting. I'd place this around the end of the 1860s or early 1870s, since the lady's hairstyle is up on top of her head with cascading curls and because the trim on this gown is more typical of that time period. The dress must be a walking outfit, since the skirt is shorter than many I've seen. Perhaps for a day at the races?