This tray is 9.5" long, just over 6" wide, 1.5" high at the center of the edging, but 2.25" tall at the tallest point of the handle.
The four feet unscrew, and I can say that the wood is plywood. However, plywood was introduced into the US in 1865, so that's not particularly helpful. (Artist boards for painters were produced and sold in New York as early as 1880.)
The stamp on the side reads 5 W.S.P.Co MADE IN U.S. AMERICA
Ultimately, what I'd like to learn is how old it is, whether it should be polished.
(admin edit - see Posting Requirements )