This is a very fine Bumastus ioxus from the Rochester Shale of New York. This large trilobite is very 3-dimensional, extremely prone, and nicely articulated - both free cheeks are even intact. The dark trilobite contrasts beautifully with the light grey matrix. The complete bug is nicely presented on the squared plate of shale. And at one and a half inches long, it is large for a Bumastus from this site. This is a very nice example of this classic Silurian trilobite.