Meek, F.B. & F.V. Hayden. 1857. Descriptions of new species and genera of fossils, collected by Dr. F.V. Hayden in Nebraska Territory, under the direction of Lieut. G.K. Warren, U.S. Topographical Engineer; with some remarks on the Tertiary and Cretaceous formations of the north-west, and the parallelism of the latter with those of other portions of the United States and Territories. Proceedings of the Academy of Natural Sciences of Philadelphia 9: 117-. Available electronically.
Meek & Hayden, 1857. Proc. Acad. Nat. Sci. 9: 145.
Meek & Hayden, 1857. Proc. Acad. Nat. Sci. 9: 145.
Meek & Hayden, 1857. Proc. Acad. Nat. Sci. 9: 146.