New middle Pliocene rodent and lagomorph faunas from Oregon and California

The purpose of this paper is the description of two rodent faunas in the collections of the California Institute of Technology. Although coming from widely separated areas, these assemblages are of approximately the same age. The first fauna to be discussed is that from Pliocene strata near Rome, Malheur County, Oregon. It exhibits some diversity of type although the associated larger mammals are known by very fragmentary remains. The second rodent fauna comes from the Kern River deposits, San Joaquin Valley, California. The Kern River rodents and lagomorphs, and the larger mammals found with them, share with other Tertiary assemblages of the San Joaquin Valley the important task of determining the time relationships between the nonmarine deposits in which they are found and the standard marine sections of the Pacific Coast. The illustrations for this paper are from photographs by the late H. Wm. Menke, and have been carefully retouched and arranged into plates by John L. Ridgway.