The most abundant fossil in the upper part of the Wapsipinicon beds at Independence and elsewhere in east central Iowa is a fine-ribbed representative of Atrypa reticularis (Linn.). This species is found in every fossiliferous horizon in the Devonian or the state. Indeed, it is worldwide in its distribution and is the "longest lived of all known organisms," ranging from early Silurian through the Devonian into the early Mississippian.
Proceedings of the Iowa Academy of Science
©1916 Iowa Academy of Science, Inc.
Thomas, A. O.
"A Highly Alate Specimen of Atrypa reticularis (Linn.),"
Proceedings of the Iowa Academy of Science, 23(1), 173-177.
Available at: https://scholarworks.uni.edu/pias/vol23/iss1/29