We thank the editors of this volume for inviting us to take part in this endeavor to honor the late C.A. Repenning. We thank R.L. Levin, Smith Center, Kansas for discovering the Fiene site, bringing it to our attention, and donating the material he collected. We thank C.J. Bell, C.N. Jass, and an anonymous reviewer for their constructive comments and for sharing their insights regarding arvicoline relationships. We thank R. Purdy of the National Museum of Natural History for the loan of specimens in his care. GSB's research is supported by the Lerner-Gray research fellowship at the American Museum of Natural History.