Hello
I don't quite understand the question your asking and if there is any answers provided but I will still give you mine.
Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.
Hope this helps!!
Have a nice day!!