This is a very fine Bumastus ioxus from the Rochester Shale of New York. This trilobite is very 3-dimensional, extremely prone, and nicely articulated - both free cheeks are intact and tightly attached. The dark trilobite contrasts beautifully with the light grey matrix. The bug is nicely presented on the semi-squared plate of shale. And at almost 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.