After cleaning the hardened black gunk off this 5-ft mystery saw, the etch shows it to be a Keen Kutter. It had mis-matched and incomplete loop handles.
The E.C. Simmons on top of the KeenKutter triangle indicates that it is a pre WWII saw. It looks a lot like a Simonds No.13.
It is taper ground, .075" at the teeth down to .050" on the back. It looks to have never been filed but I have yet to get to work on it. It has crazy big and irregular sets, from .008 to .029 - you can see the 13 and 22 on the photo of the etch for .013" and .022" set.