Use the data you've recorded from the previous activity to arrange the rock layers from oldest to youngest on the geologic time scale. Determine the identity of the unknown fossil by using the Fossils chart.

TOOLS

Paleozoic Era

433 417

359

542

490

299

250

+

+

million

years ago

Basalt

Limestone with

unknown fossil

Cambrian

Ordovician

Silurian

Devonian

Carboniferous

Permian

Sandstone with

trilobite

Shale with

ammonite

Che