ANTIQUE PITCHER FROM POSSIBLY LATE 1700'S OR 1800'S

This pitcher/vase was found by my husband in 1965 when he was 11. He found it near Fort Montgomery, NY in his backyard and has held on to it for all these years. This was less than 1/4 mile from the Hudson. It was on it's side and about 1/2 inch was showing, the rest was buried. It is in mint condition. No cracks, No chips, No scratches. We have tried to do some research on the name on the bottom. Elwell. There were two men who fought in the war with that name in the late 1700's. We have spoke with a analyst in the museum there in New York who wanted us to donate it to the museum. We have shown it to many antique dealers and were told it is exquisite. We have been told it could be worth quite a bit.   We have some documents in regards to the Elwell's.