Middle Devonian (Eifelian) conodonts from the Spillville Formation in northern Iowa and southern Minnesota

The Spillville Formation is a newly recognized formation in northern Iowa and southern Minnesota that is unrelated lithostratigraphically to the Cedar Valley Formation in east-central Iowa, a unit with which it has been correlated for most of this century. The Spillville is overlain by a clastic interval that correlates on lithostratigraphic evidence with the Kenwood (middle) Member of the Wapsipinicon Formation, below the Cedar Valley in...