A Miocene mammalian fauna from southeastern Oregon

Abstract

In the course of paleontological explorations in southeastern Oregon during the summer field seasons of 1928 and 1929 California Institute parties have been fortunate in securing collections of mammalian remains in Tertiary deposits exposed in the northern portion of Malheur County. Attention was first directed to the so-called Skull Spring occurrence by Mr. C. J. Bush of Harper, Oregon. The fossil locality is twenty-eight miles south of Harper, Malheur County, Oregon, and approximately three miles northwest of Skull Spring. The beds in which the mammalian remains were found occur in a small basin draining southward and eastward into the Owyhee River. The local drainage is a part of a tributary known as Dry Creek or Beaver Creek. The northern margin of the basin is situated on the divide between the Owyhee and Malheur systems. Beyond this divide the gradient is northward through Red Ridge basin and Cottonwood Creek to the Malheur River at Harper flats. Field operations were conducted with the cooperation of the Carnegie Institution of Washington and were under the direction of Dr. Chester Stock of the California Institute of Technology. The author is indebted to Dr. Stock for the opportunity to study the fauna and for valuable advice and criticism during the progress of the investigation. The author was associated in the field with Dr. Chester Stock, E. L. Furlong and L. C. Hookway during the first season; and with E. L. Furlong, F. D. Bode, S. W. Lohman and E. R. Inglee during the second summer. Acknowledgment is also made of the courtesy extended by Mr. Donald R. Dickey and staff at the California Institute of Technology in permitting unreserved use of the Dickey collection of Recent mammals. The drawings for the text-figures were made by Mr. John L. Ridgway. The photographs reproduced in the plates have been carefully and accurately retouched by Mr. Ridgway.