The oldest rocks of the Dingle Peninsula are those of Clogher Head. Fossils trilobites are common in the nearby cliffs. Well, not so common that finding one isn't a thrill. Here's one from a recent walk.
Trilobites -- so called because their bodies have three lobes -- were fabulously successful marine animals for several hundred million years. Big ones, little ones, skinny ones, squat ones. Then about 250 million years ago they disappear from the rocks.
Very likely they were done in by the impact of a sizable asteroid, and not only trilobites became extinct. This little fellow lived in the trilobite heyday, oblivious of rogue rocks from space that make life on Earth a dicey thing.