312 University of California Publications in Geology [Vol. 13 



the Oregon form and the genus Peratherium. Mr. Gidley in a letter 

 dated June 11, 1921, also indicated the didelphid affinities of the 

 Logan Butte specimen. Through the kind efforts of Dr. Gregory and 

 Mr. Granger the writers were permitted to borrow materials of Pera- 

 therium for comparison. 



Occurrence 



The John Day Oligocene deposits occurring south of the type 

 locality in the John Day Valley are well exposed in the drainage basin 

 of the Crooked River southeast of Prineville. Along Camp Creek, a 

 tributary of the Crooked River, the beds consist of volcanic ash, red- 

 dish brown and bluish green in color, and resemble the lower and 

 middle John Day beds in the John Day basin. 1 At Logan Butte, 

 a landmark near the head of Camp Creek and approximately fifty 

 miles southeast of Prineville, Crook County, Oregon, the green colored 

 tuff's of the John Day, in which occur the marsupial remains here 

 described and many specimens of oreodons, are distinctly folded. The 

 beds are overlain uneonformably by a later Tertiary formation closely 

 resembling in its lithological characters the Rattlesnake Pliocene 

 deposits of the John Day Valley. The Oligocene fauna, as represented 

 by the collections made during the summer of 1920, has not been 

 completely reviewed. Dr. John C. Merriam 2 determined the presence 

 of three carnivores, Mesoeyon brachyops Merriam, Temnocyon alti- 

 genis Cope, and Archaelurus debilis major Merriam, from remains 

 obtained in 1899-1900. 



PERATHERIUM MEREIAMI, n. sp. 



Type Specimen. — A fragmentary skull and lower jaw, no. 24240, 

 Museum of Palaeontology, University of California, from the John 

 Day Oligocene beds at Logan Butte, eastern Oregon. This species is 

 named in honor of Dr. John C. Merriam. 



Specific Characters. — Skull larger than in Peratherium fugax 

 (Cope) from the White River Lower Oligocene of Colorado and 

 smaller than in Lower Miocene species of Peratherium from Europe. 

 The two posterior premolars of the superior dentition are relatively 

 not so narrow as in P. fugax. M 1 is more robust than the correspond- 

 ing tooth of P. f ugax. 



1 Russell, I. C, Preliminary report of the geology and water resources of 

 central Oregon, U. S. Geol. Surv. Bull. 252, 1905. 



2 Merriam, J. C, Carnivora from the Tertiary formations of the John Day 

 region, Univ. Calif. Publ. Bull. Dept. Geol., vol.' 5, pp. 1-64, pis. 1-6, 1906. 



