OCR Text |
Show Animal indicators confined to, or particularly characteristic of, the Transition Zone include the tuft- eared squirrels, certain local races of wood rats and pocket gophers, and other small rodents, wild turkey, and band- tailed pigeon. Upper Sonoran Zone.- This and the next zone take their names from the Province of Sonora in Mexico, from which they derive some of their plants and animals. Climatically, the Upper Sonoran Zone is considerably cooler than much of Sonora. It comprises most of the broad lower valley lands of the basin except in southern and western Arizona, southern Nevada, and adjacent California, where it gives way to a still warmer climate and becomes the principal life zone of the foothills, ex- Figure 8.- Transition Zone- Shivwits Plateau. |