All the trilobites in this category were self collected from a private quarry near Llandrindod Wells in Wales (UK). The rocks at this site are Ordovician in age (Llanvirn Series, roughly 460 million years). The site has been interpretted as a shallow water environment and a breeding ground for Ogyginus trilobites. It's thought that many of these trilobites were killed and rapidly buried by volcanic eruptions. There are several species of trilobite found here, but fossils of Ogyginusa are by far the most common.