This Socony Motor Oil sign (Standard Oil Company of NY) was also sandwiched between the floor layers. Why? Maybe someone thought the metal would provide some support?
Socony is now Mobil.
(Socony Motor Oil sign.)
In 1931, Socony merged with Vacuum Oil, and became the Socony-Vacuum Oil Company. So this sign must have been created before 1931.
Meanwhile, it was also deemed necessary to remove the kitchen walls (sheetrock and old plaster), to expose the wiring… because the room, of course, needed to be rewired.
Altogether, there were eight layers of flooring. And when all the layers were finally removed, and the wall material removed, my kitchen looked like this: