A new Lagerstätte from the Middle Ordovician St. Peter formation in northeast Iowa, USA

Abstract

A new fossil fauna has been discovered from a recently recognized shale unit within the middle Ordovician SL Peter Formation in northeast Iowa. It contains a variety of invertebrates and vertebrates, including soft body tissues, impressions, and 3-dimensional-preservations. The exceptional preservation reveals a new Konservat-Lagerstätte, the Winneshiek Lagersätte, and opens a unique window into the community that inhabited the margins of the Laurentian cratonic seaway during Middle Ordovician transgression. Among the fossils, several conodont assemblages, including the apparatus of enigmatic coleodontids, are preserved. Some conodont assemblages associated with soft body tissues are particularly noteworthy. © 2006 Geological Society of America.