A Pensylvanian (Naco Group) horshoe crab (probably Euproops) found near Payson, Arizona.
This may be the oldest such crab found in Arizona.
Click on images for full scale version.
Low magnification view of the whole piece split open.
A view of just the positive half.
50x view of the positive half taken with a 1.3 Mega pixel Celestron 44302 Digital Microscope.
50x view of the negative half taken with a 1.3 Mega pixel Celestron 44302 Digital Microscope.