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 even intact. The dark trilobite contrasts beautifully with the grey matrix. The bug is nicely showcased on the plate of dense shale. And at over one and a quarter inches long, it is large for a Bumastus from this site. This is a very nice example of this classic Silurian trilobite.