I have been working on undo-ing some linoleum that was probably added in the '50s and I uncovered what must be the original kitchen floor tile.
Looks like... yes... asbestos! Old grey fibrous and often cementitious type materials are usually asbestos. Here you can see the linoleum looks like that, on top of Masonite, on top of Maybeck-looking (and asbestos-looking) flooring on top of burlap? I would've expected tar paper.
Back to the suspected Maybeck feature...
Does the above pattern look familiar?