The trilobites that come out of the Haragan formation at Black Cat Mountain are amoung the worlds best. One of the more common species is Paciphacops logani. Below are several specimens I purchased at a local fossil and mineral show. The first three specimens I have since traded away to other collectors but the last specimen is still with me.
Specimen #3 - This piece has two trilobites on it and almost stayed with me because of the arrangement.
Specimen #4 - This is my favorite because of the association with a Rhynconellid type (likely a Stegerhynchus sp. based on the shell shape and over hanging pecidle) brachiopod.
All four specimens came from the Haragan formation at Black Cat Mountain near Clarita, OK. the Haragan formation is thought to be lower Devonian, (Lochkovian stage). It roughly corresponds to the Birdsong shale of Tennessee and the Helderberg
Fauna of New York, Pennsylvania and Maryland.