As you can see and as I rechecked, there is no silver marks on the bottom of this antique...

Thank you for checking for marks and thank you for contacting Mearto with your appraisal inquiry.

It is a very nice covered vegetable dish, however, I am not quite sure that it is made of silver when there are no silver marks. Usually there would be some kind of silver marks either on the base or the lid, by the handles on such a large piece. You may be able to determine if it is silverplate by looking at the edges where the silver has been most worn/polished to see if a yellow or red metal shines though the silverplating.
Or you can have your covered dish tested by a silversmith to determine the material.
It was a very popular piece of hollowware in the Victorian times and could be either American or English.

The estimate provided is (presuming it is silverplated) for a well-advertised specialised silver auction, where I believe the covered dish has the best chance of realising its fullest potential.
Please let me know if you have any additional questions. I’m happy to help.
Thank you

Thank you for the response but I see no appraised value assigned in your response, assuming it is silver-plated... There is no red/yellowing. The interior of the piece is pitted. Please advise?

The interior pitting possibly comes from years of use. I would suggest that you leave that as it is. Its part of the charm when living with antiques :)