53 



up the most valuable pair of animals in the outfit. A hinny 

 has toughness, and power of subsisting on httle water and less 

 food, to about the same extent as a mule. The chief distinc- 

 tion between the two, outside of appearances, is tempera- 

 mental, for the mule considers itself a horse, while the less 

 egotistical hinny aspires only to be a burro. Thus is demon- 

 strated the strength of filial instinct for the mother. One 

 has but to lead a mare, and all the mules will follow; in like 

 manner, the hinnies flock in the tracks of a she-ass. 



Just across the borderline from Calexico, a sandy-haired, 

 blue-eyed Mexican, with an automatic rifle and a belt full of 

 cartridges, inspected our customs receipts, and then passed 

 us along with salutations. We followed a road that led 

 through six miles of reclaimed, cultivated fields, as fertile as 

 the country on the American side of the line, until we came to 

 the final- artery of the Imperial irrigation system, at the 

 edge of the desert. Its muddy water was the last supply 

 this side of Hardy's Colorado, so we camped for lunch. 

 Meadowlarks^ at the outposts of their range, were singing 

 in the alfalfa fields; we were to hear them no more until 

 we had returned from the wilderness to the agricultural 

 country of which they seem to be a part. Coots, scaup ducks, 

 and baldpates were feeding in neighboring puddles of irrigation 

 water, and ox-eyes pattered around the margins. 



When we saddled and struck out southward, we crossed 

 first several miles of rather dense mesquite (Prosopis glandu- 

 losa), the visible inhabitants of which were doves, gnatcatchers, 

 and desert quail, with an occasional foraging owl (Speotyto). 

 We were ascending, by imperceptible stages, the southerly 

 slope of the Salton Sink, and were within a few miles of the 

 gulch of the New River. Presently the cracked, periodically 

 flooded soil of the mesquite groves gave way to sandy seolian 

 areas in which the creosote bush {Larrea tridentata) was the 

 dominant plant, although bunch-grass, chollas and prickly 

 pears, one or more species of Atriplex, and small ocotillas, 

 became increasingly common as we approached the Cerro 

 Prieto (Black Butte). Vegetation of this general character 

 prevailed as far south as a point east of the Borrego (Mountain 



