Fossil Gastropods
What is the relative age of a rock layer containing these fossils?

Fossil Type ------- Oldest Occurrence-----Youngest Occurrence

Foraminifera -------Silurian --------------------Quaternary
Bryozoan------------Silurian --------------------Permian
Gastropod-----------Devonian ------------------Pennsylvanian
Brachiopod----------Silurian --------------------Mississsippian
Bivalve----------------Silurian --------------------Permian
Gastropod-----------Ordovician ---------------Devonian
Trilobite---------------Silurian -------------------Devonian
Ostracod-------------Devonian -----------------Tertiary
Brachiopod-----------Cambrian ----------------Devonian

It doesn't have to be the exact age, just give it your best shot.
Based on the age determined, could this group be index fossils?
Thanks, what do you think the age of this rock layer is?

None of these fossils could be index fossils, they have all been around a very long time.

Index fossils are very widespread, but are the reamins of organisms that have been around for a very short period of time

In order of oldest first appearance:
Brachiopod-----------Cambrian ----------------Devonian
Gastropod-----------Ordovician ---------------Devonian
Trilobite---------------Siluri... -------------------Devonian
Brachiopod----------Silurian --------------------Mississsip...
Bivalve----------------Siluria... --------------------Permian
Bryozoan------------Silurian --------------------Permian
Foraminifera -------Silurian --------------------Quaternary
Gastropod-----------Devonian ------------------Pennsylvania...
Ostracod-------------Devonian -----------------Tertiary

last appearance,in order of most recent last appearnce
Foraminifera -------Silurian --------------------Quaternary
Ostracod-------------Devonian -----------------Tertiary
Bivalve----------------Siluria... --------------------Permian
Bryozoan------------Silurian --------------------Permian
Brachiopod----------Silurian --------------------Mississsip...
Trilobite---------------Siluri... -------------------Devonian
Gastropod-----------Ordovician ---------------Devonian
Brachiopod-----------Cambrian ----------------Devonian



Items Recently Purchased From This Site: