Agree, if it says Electro plate that would be silverplate. Shell dishes are all over the place, and have been really popular for the holiday table. It is a bit different and nicer then most I have ran into or have. Around Holiday time on ebay you can sell these, but not for much at all. Too many are available. Your Item is most likey Post 40's to early 60's in age, this was the time when silverplate was made almost exclusively for the Holiday table. You have a really nice sample of a Shell dish.