"Beecher Trilobite Bed" The Beecher Trilobite Bed (Upper Ordovician) is one of the world’s finest examples of a trilobite lagerstätten. This site has yielded a rich and nearly mono-specific assemblage with the ventral anatomy and musculature of Triarthrus eatoni intact. Media: Adobe Photoshop. Click on arrows to get closer or view next illustration.