Added to the file, a rather nice radioactive (shows Ra-226 daughters) Trilobite fossil that I
collected in Morocco on 1994/1995 field trip.
The rock to the right is the overburden, the part of the rock that covered the trilobite and helped
created the fossil. It's rare to come back with such a nice pair, fitting together perfectly like a jigsaw puzzle.
From the Paleozoic Era, trilobites went extinct in the Great Permian Extinction, 251,000,005 years ago
before the dinosaurs arose.
Have fun
Geo