Two rodents and a lagomorph from the Sespe of the Las Posas Hills, California

One of the largest vertebrate assemblages to be recorded from the Sespe deposits of Southern California, representing an upper Oligocene age, was obtained by the California Institute of Technology in the Las Posas Hills of southern Ventura County. The description of this fauna by Dr. Chester Stock is now in progress. The author of the present paper has been granted the privilege of describing the rodents and lagomorphs from this locality. I wish to thank Dr. Stock, not only for permission to study the material, but for a critical reading of the manuscript. The photographs reproduced in the plate have been carefully retouched by Mr. John L. Ridgway.