Middle Devonian Brachiopods of Southeastern Wisconsin

Abstract

Twenty-nine genera, forty-eight species, and five subspecies of brachiopods are recognized from the Middle Devonian formations of southeastern Wisconsin. Two species and four subspecies are new. The presence of Trigonoglossa truncata in the Wisconsin section seems to substantiate the extension of the range of this Pennsylvanian genus into the Middle Devonian as suggested by Girty, and the existence of well-preserved Lingulidiscina in the Milwaukee Formation supports the validity of this genus, previously questioned by Girty. Correlation of the Lake Church formation is obscure because of incomplete collections from localities now inaccessible. However, distinctive Milwaukee Formation species show affinities with Upper Middle Devonian Cedar Valley brachiopods of Iowa, indicating the possibility of a connection between these areas during late Hamilton time.