MAMMALS OF THE MEXICAN BOUNDARY. 37 



considerable area, descending, in Millers Canyon, as low as 2,027 

 meters (6,650 feet). The Mexican white pine is a tree of the Cana- 

 dian life zone, and does not descend as low as the Douglas spruce. 

 In its range it is usually associated with the Douglas spruce, aspen, 

 and Gambel oak. It is a tree from 10 to 30 meters (30 to 100 feet) in 

 height, bearing long, resinous cones, whose seeds are attractive to 

 squirrels. 



PINUS CEMBROIDES Zuctarini. 

 KEXICAN FlSON. 



This nut pine was first met with on the Big Hatchet Mountain 

 (altitude 2,545 meters or 8,350 feet), about 110 miles west of the 

 Rio Grande, in Grant County, New Mexico. It is the principal tree, 

 and the only pine, of this mountain, covering most of the north and 

 east slopes above 6,000 feet. There are a few isolated trees in 

 the Dog Mountains. It also reaches to the summit of the San Luis 

 Mountains (altitude 2,400 meters or 7,874 feet), which it descends 

 to the level of 1,826 meters (5,990 feet) ; but though not uncommon 

 in mountains to the westward, it was nowhere the dominant tree 

 except on Big Hatchet Mountain. Its range extends westward to 

 the Pajaritos Mountains, and is the only pine found west of the 

 Santa Cruz Valley, until the mountains of the Coast Range, in 

 California, are reached. On the San Jose, Huachuca, and Patago- 

 nia mountains its range extends from 1,829 meters (6,000 feet) up- 

 ward. The Mexican pifion has, apparently, a higher altitudinal 

 range than Pinvs edulis, having been found by us at a little less than 

 2,740 meters (9,000 feet) above sea level on the Huachuca Mountains. 



PINUS EDULIS Engelmann. 

 PINON. 



Specimens of this pine were brought to the author at Fort Clark, 

 Texas, by hunting parties sent out to the mountains northwest of the 

 post. The species was not met with elsewhere on the Boundary, 

 though its range extends from western Texas across New Mexico 

 into northeastern Arizona, in which region it, together with the red 

 juniper, marks the limits of the Upper Sonoran Life Zone. 



, PINUS MONOPHYLLA Torrey and Fremont. 



SINGLE LEAF PINON. 



Specimens of this pine were collected in the highest notches of the 

 Coast Range Mountains of California, near the Boundary. It does 

 not occur on the Mexican line east of the Colorado Desert; but in 

 1884 I saw an extensive forest of what I suppose to have been this 

 species occupying a zone between the Santa Fe Pacific Railroad 

 and the Colorado River east of Peach Springs, in Arizona. 



