The Spence Shale Member of the Langston Formation is a Cambrian (Miaolingian: Wuliuan) Lagerstätte in northeastern Utah and southeastern Idaho. It is older than the more well-known Wheeler and Marjum Lagerstätten from western Utah, and the Burgess Shale from Canada. The Spence Shale shares several species in common with these younger deposits, yet it also contains a remarkable number of unique species. Because of its relatively broad geographic distribution, and the variety of different palaeoenvironments and taphonomy, the fossil composition and likelihood of recovering weakly skeletonized (or soft-bodied) taxa varies across localities. The Spence Shale is not only widely acknowledged for its collection of soft-bodied taxa, but also for its abundant trilobites and hyoliths. Recent discoveries from the Spence include problematic taxa and insights about the nature of palaeoenvironmental and taphonomic variation between different localities.
Scientific editing by Philip Donoghue