Mid 50s Elgin Automatic 6823
This Elgin is probably from 1955 and likely debuted along with the similar looking Niagara.
This model, with case number 6823, is 10k gold filled and has a nicely machine decorated bezel.
The dial has a nicely done, pressed, Sunday design, with gold drilled minute markers and raised gold hour markers.
It uses the 17 jewel, Swiss sourced 643 automatic movement.
Also, note the hands. When I first received the watch, I just assumed it was fitted with improper hands, but I can into possession of another 6823 and it has the same unusual hands.