Tremadocian

Tremadog (formerly Tremadoc) is a village in the community of Porthmadog, in Gwynedd, north west Wales; about north of Porthmadog town centre. It was a planned settlement, founded by William Madocks, who bought the land in 1798. The centre of Tremadog was complete by 1811 and remains substantially unaltered. Tremadog hosted an unofficial National Eisteddfod event in 1872.

Calymene is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. Calymene is closely related to Flexicalymene, and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments.

Burgess shale-type deposits