Early Amercian Pottery Mark

I have a lovely plate from my grandparents who lived in Haverhill, MA and would like to know a little more about the plate. If you could provide the approximate age and value of this item and hopefully a little bit of the history. Is this plate a "decorative" item or part of a set of dishes? Unfortunately, my grandparents have passed away and I know very little and have no one to ask in the family. I have provided a picture of the plate and the stamp on the back. Any information would be very appreciated.