Looks like a beach plum. They make good preserves.

Beach plum, prunus maritima. Probably premier beach plum?

Thanks. The online descriptions of Prunus Maritima describes the tree. I'll return to it next week and taste one. If I like it I'll take a cutting to root and try it in my backyard which has sandy soil. I was impressed at how healthy it looked.

I don't know anything about Beach Plum, except buying a pot of jam on Cape Cod, but I do know that the taste of fruit is not necessarily a guide as to whether it will make good preserves. You might find it unpleasant raw but it will make great jam.

Exactly and the quince tree is proof of that statement.