- This spectacular Triarthrus eatoni trilobite is preserved ventrally (from the underside) and exhibits remarkable preservation of soft body parts. on a single slab. It was collected in the Late Ordovician shale of the Whetstone Gulf Formation in Lewis County, New York. There are only a few locations in the world where trilobites are preserved with soft body parts and not just an empty shell. It is even rarer to find soft body preservation with pyrite (iron sulphide or fool’s gold). Preservation of pyritized trilobites with their legs, gills and antennae happened under extremely specialized environmental conditions. The trilobites were rapidly buried in mud which was low in organic matter, lacked oxygen but were rich in highly reactive iron.
The mudstone bed where these gorgeous trilobites were collected is only about 4 – 10 centimetres thick! It is very probably that future specimens of pyritized trilobites with soft body preservation will be extremely difficult to find and that the thin layers will soon run out. Don’t miss out on their opportunity to get one of these unique treasures in the fossil world.
The trilobite measures 1.9cm - not including antennae (large for pyrtitized Triarthrus from this site). Ventral specimens (preserved from the underside) are rarer than dorsal specimens and much harder to discover, given that they are barely visible under the matrix before prepared.
- View this page to learn more about pyritized Triarthrus trilobites, including how they are discovered and prepared. Learn interesting general facts about trilobite fossils here. Follow this link to learn how fossils become pyritized.