1970. Influence of late-glacial and post-glacial events on the distribution of Recent mammals on the Northern Great Plains. Pp. 355-394, _in_ Pleistocene and Recent environments of the Central Great Plains (W. Dort, Jr., and J. K. Jones, Jr., eds.), Univ. Press of Kansas, Lawrence, xii + 433 pp. HOFFMANN, R. S., and D. L. PATTIE 1968. A guide to Montana mammals.... Univ. Montana, Missoula, x + 133 pp. HOFFMANN, R. S., P. L. WRIGHT, and F. E. NEWBY 1969. Distribution of some mammals in Montana. I. Mammals other than bats. Jour. Mamm., 50:579-604. HOFFMEISTER, D. F. 1951. A taxonomic and evolutionary study of the pinon mouse, Peromyscus truei. Illinois Biol. Monogr., 21: ix + 1-104. JONES, J. K., JR. 1964. Distribution and taxonomy of mammals of Nebraska. Univ. Kansas Publ., Mus. Nat. Hist., 16:1-356. JONES, J. K., JR., and H. H. GENOWAYS 1967. Annotated checklist of bats from South Dakota. Trans. Kansas Acad. Sci., 70:184-196. JONES, J. K., JR., and F. R. HENDERSON 1963. Noteworthy records of foxes from South Dakota. Jour. Mamm., 44:283. LILLEGRAVEN, J. A. 1970. Stratigraphy, structure, and vertebrate fossils of the Oligocene Brule Formation, Slim Buttes, northwestern South Dakota. Bull. Geol. Soc. Amer., 81:831-850. MILLER, G. S., JR., and R. KELLOGG 1955. List of North American Recent mammals. Bull. U.S. Nat. Mus., 205: xii + 1-954. OVER, W. H., and E. P. CHURCHILL 1945. Mammals of South Dakota. Univ. South Dakota Mus., 56 pp. (mimeographed). PFEIFER, W. K., and E. A. HIBBARD 1970. A recent record of the swift fox (_Vulpes velox_) in North Dakota. Jour. Mamm., 51:835. SWENK, M. H. 1941. A study of subspecific variation in the Richardson pocket gopher (Thomomys talpoides) in Nebraska, with description of two new subspecies. Missouri Valley Fauna, 4:1-8. VISHER, S. S. 1914. Report on the biology of Harding County, northwestern South Dakota. Bull. South Dakota Geol. Surv., 6:1-103. YOUNG, S. P. 1944. Their history, life habits, economic status, and control. Pp. 1-385, _in_ The wolves of North America (S. P. Young and E. A. Goldman), Amer. Wildlife Inst., Washington, D.C., xx + 636 pp.