Some fossils will be. Forams, for example, can be found in both shallow and deep-water sediments.
Beyond that, the geological scale was created long before dating methods came to pass. Geologists instead relied on estimates of how long various sedimentary formations took to be laid down. Also, if you look at the fountainhead of geology - the British Isles - you have clear progressions from Cambrian into the Carboniferous - and more complex life appearing in each age. So on the most fundamental geological level, there is a progression life.
But that goes right back to the same circular reasoning/initial assumptions issues as before.
Great. Geologists relied on "estimates" of how long sedimentary rocks took to be laid down. How do we know their "estimates" are right, or even remotely valid at all? We don't.