Using your tip I have identified the spoon as the Gorham 1897 Lancaster pattern. Thanks so much for the quick response. I wonder why an American piece includes the British Sterling and Birmingham hallmarks?
This is one of a collection of 10 spoons I own with similar (but not the same) marks that include a Standard, City, & Date, but no tax mark. This one does not include a makers mark either. I don't know what the "D" in the circle is either. Spoon is just short of 6 inches long. It shows...