English: Geodized brachiopod fossil lined with calcite with a single crystal of sphalerite; Middle Devonian; Milwaukee Formation; Lindwurm Member; Milwaukee County, Wisconsin; MPM P29133; collected by K.C. Gass; photograph originally published in K.C. Gass, J. Kluessendorf, D.G. Mikulic, and C.E. Brett, 2019. Fossils of the Milwaukee Formation: A Diverse Middle Devonian Biota from Wisconsin, USA. Siri Scientific Press, Manchester, UK.