Vol. XXIX, pp. 129-132 September 6, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



OVIS SHELDONI, A NEW MOUNTAIN SHEEP FROM 

 SIERRA DEL ROSARIO, SONORA, MEXICO. 



BY C. HART MERRIAM. 



When hunting mountain sheep in the Gila and Tule Ranges 

 in southwestern Arizona and the Viejo and Pinacate Ranges in 

 northern Sonora in 1913 and 1914, Charles Sheldon of New 

 York noticed a low ridge, the Sierra del Rosario, lying parallel 

 to, and to the southwest of the Gila Range (also known as the 

 Sierra de las Tinajas Altas), from which it is separated by about 

 12 miles of desert. To the northwest, west, and south there 

 are no mountains, the desert stretching all the way to the Colo- 

 rado River and Gulf of California. 



Sheldon knew that Carl Lumholtz had ridden out to El 

 Rosario and reported seeing sheep tracks there. Believing that 

 the complete isolation of the range in connection with the 

 nature of the surrounding desert would prevent sheep from 

 crossing to it, Sheldon felt that the animal would be likely to 

 differ from that of the adjacent mountains. In the hope of 

 determining this point, he undertook, in the early part of 

 March of the present year, a special trip to El Rosario, carrying 

 water from Tinajas Altas, 20 miles away. On his way back 

 (March 15, 1916) he wrote me from Wellton, Arizona : 



I have just returned from a very hard hunt for sheep in the mountain 

 of El Rosario. This mountain is parallel with the Gila Range, 12 miles 

 distant, from which it is separated by a flat desert with six or seven miles 

 of soft sand dunes. The part of the mountain large enough for sheep is 

 five miles long and only 1500 to 1700 feet in altitude, and is of the honey- 

 comb type like the Gilas. There is not a drop of water in the whole 



28— Proc. Biol. Soc. Wash., Vol. XXIX, 1916. (129) 



