Beautiful old Silver/Silverplate Tray American? Mfg mark

[siggy1]

I need your help to identify this Mfg Mark. I don't know if the tray is silver or silverplate. The tray is 21 1/4 X 12 1/2" and weighs 2lb 12oz (1260 Grams) It has 4 Victorian style feet. At one time the tray had handles which were broken off. I have included a picture of the Mfg mark and a picture of the tray. The mark was filled in with marker in order to get it to show up. I would love to know what each symbol in the mark stand for and where the tray was made. Any information at all will be much appreciated. Many thanks! siggy1

Mfg Mark on tray:

Picture of Tray: