The Dalmanites trilobite lived in the ocean during the Silurian period between 450 - 415 million years ago.
Dalmanites used its "shizochroal eye" to get a remarkably clear look at its undersea world. The unique eye was made of hundreds of relatively large, thick lenses that were made of the mineral, calcite. The periscope-esque eyes allowed for a wide range of view.
This particular specimen clearly shows the eye facets and armor that kept it protected. The specimen has been retouched with a dark gray color to help it stand out clearly from the shale.
Species: Dalmanites limulurus
Age: Silurian (443 - 416 million years old)
Formation: Rochester shale
Locality: Middleport, New York
Size of Plate: 3.88 x 3.06 x .5 inches
Size of Specimen: 2.38 x 1.25 inches
Weight: 5.8 oz.