In sedimentary rock, the age of the deposition is what provides the time frame of the rock formation.
“Rock formation” is an ambiguous term in this context. You pick up a rock ... when was it formed? The geologists answer is the date of the agglomeration of the material of the rock, yet in common terms, a “rock formation” refers to the apparent configuration of the constituent rocks, however ancient their “formation” may have been.
So, we’re involved in a purely rhetorical exercise. If that rock was 200 million years old, it was still 200 million years old after it was tipped over.