Over 400 million years ago, the muddy seafloor stirred below a deep tropical sea.  Slowly, the armored headplate of a multi-segmented crea...

It appears this is a complete Calymene trilobite of the Middle Silurian Period.  It is about 5 cm long and will be a challenge to coax o...

The Trimerus delphinocephalus (Green, 1832) trilobite of the Silurian Period. This first image is from a 1910 book. The picture is to giv...