Polystrate Whale Fossil: Diatomaceous earth is formed of the remains of dead diatoms, and because these are microscopic single-celled algae, old-Earth geologists naturally believe that diatom deposits represent the passage of long eons of geologic time.
A Polystrate Fossilized Jellyfish School: Seven sedimentary layers in central Wisconsim had been previously described by old-earth geologists as taking a million years to form. Now, some soft-bodied jellyfish are making that claim hard to maintain. Jellyfish have no skeleton.
Polystrate fossils are those which span a number of geologic strata. Typically polystrates are trees but they could result from the remains of any organism or even from the remains of a collected group of organisms such as a school of jellyfish buried in layered sediments that allegedly were deposited over a million years.