MAMMALS OF THE MEXtCAN BOUNDARY. 359 



The dens of beavers are usually dug in the bluff banks of streams, 

 and have the entrance at a considerable depth below the surface of the 

 water. At the back part are usually one or more openings, probably 

 for the purpose of admitting the air, which are concealed by brush and 

 weeds. At Fort Verde a beaver den was partially opened, and a bull- 

 dog that had earned the reputation of being a hard fighter was ad- 

 mitted. In the fight that ensued the dog was badly beaten, and could 

 not again be induced to attack a beaver. 



Mr. Stuart Daniels found beavers on the Sonora River, Mexico. He 

 also found them in abundance on the Gila River, Arizona. On the 

 Boundary Survey they were found on the San Pedro River and on 

 Babocomeri Creek, one of its tributaries in Arizona. Two trappers 

 whom we met at Yuma, i\Tizona, in JMarch, 1894, had recently arrived 

 from a 200-mile trapping expedition dowm the Gila River. They had 

 shipped a number of beaver and raccoon skins taken during this trip, 

 but found no beavers on the lower portion of the Gila. I saw old 

 beaver cuttings on the Gila in the vicinity of Adonde Siding, Arizona, 

 in February, 1894. Residents said that there had been scarcely any 

 beavers on the lower Gila since the flood of February, 1891, which 

 washed them all out. One man told me that beavers were then (Feb- 

 ruary, 1894) working extensively at Mohawk, on the Gila. Beavers 

 were formerly found at Gila City, but had been driven out by pre- 

 vious floods. In the years 1893 and 1894 a colony of beavers was' 

 located about 12 miles below Yuma, on a lagoon of the Colorado 

 River. Seven of them were trapped by Mr. Smart, of our party. 

 Beavers are common on the Colorado, and doubtless sometimes ascend 

 the Salton and New river lagoons of the Colorado Desert during sea- 

 sons of overflowing; but we saw no signs of them at the time of our 

 visit away from the Colorado River in that region. 



No signs of beavers were seen by us on Cajon Bonito Creek or the 

 San Bernardino River, terminals of the Yaqui River; but Mr. Hall, 

 who resided in the Guadalupe Canyon, informed me in 1892 that he 

 had seen their cuttings lower down on Cajon Creek; but I failed to 

 discover them there. 



