I found this last Saturday in Brookfield, Madison County, New York. It’s pretty beat up but there are some features that can still be made out. I was wondering if it might be a bellacartwrightia rather than a greenops, which was my original thought.
According to Karl A. Wilson’s Field Guide to the Devonian Fossils of New York, one way to tell the difference is the number of lenses in the eye in a vertical row. For greenops there is maximum of 6. This trilobite has 7 in some places.
A picture of the eye, showing a vertical row of 7 lenses.
A top view of the trilobite
A side view
A view of the pygidium
Thanks for looking