INTRODUCTION

This chapter examines a variety of rare, small, mainly Chadronian and Orellan carnivorans, which occur in rocks of the White River Group or equivalents in North and South Dakota, Wyoming, Nebraska, Colorado, Montana, and Saskatchewan. These include the genera Subparictis, Campy locynodon, Drassonax,? Amphicynodon, Mustelavus, and Palaeogale. The first four are assigned to the Ursoidea, the superfamily containing the extant Ursidae and Pinnipedia. Subparictis is a member of the Subparictidae, a new family which also includes Nothocyon and probably Parictis. Campylocynodon, Drassonax, and? Amphicynodon major are amphicyno-dontines, a subfamily that is much better represented in the Oligocene of Eurasia (Teilhard, 1915; Cirot and de Bonis, 1992). Mustelavus is a very primitive North American member of the Musteloidea, the superfamily which includes the Procyonidae and Mustelidae. The affinities of Palaeogale have not been resolved, but it is probably a primitive feliform. Amphicynodontines, musteloids, and Palaeogale all have a Holarctic distribution in the Oligocene, but their earliest records are in the late Eocene of North America.