LIST OF ILLUSTEATIOB'S. 



Plate I. Map showing stations along the land 'boundary between Mexico 



and the United States from the Eio Grande to the Pacific . Frontispiece 



Facing page. 

 II. Map showing differentiation tracts of the Mexican Boundary Line. . 23 



III. Fig. 1. — Pinus ponderosa. 



Fig. 2. — West foot of San Luis Mountains 3S 



IV. Fig. 1. — Juniperus califomica. 



Fig. 2.— Salix taxifolia - 42 



V. Fig. 1. — Yucca radiosa. 



Fig. 2. — Quercus gambelii 44 



VI. Fig. 1. — Populus fremontii. 



Fig. 2. — Across the Eio Grande River 48 



VII. Fig. 1. — Quercus agrifolia. 



Fig. 2. — Quercus hypoleuca 53 



VIII. Fig. 1. — Cereus giganteus. 



Fig. 2. — Cereus thurberi 65 



IX. Fig. 1. — Chilopsis linearis. 



Fig. 2. — Eio Grande opposite the First Monument 68 



X. Fig. 1. — Eastern edge of Animas Valley. 



Fig. 2.— San Pedro Valley 92 



XI. Fig. 1. — View down Millers Canyon, Huachuca Mountains. 



Fig. 2. — Patagonia Mountains, showing Emory Oaks 102 



XII. Fig. 1.— Monument No. 126, Elevated Central Tract. 



!irig. 2. —Western part of Elevated Central Tract. . . .■ 107 



XIII. Fig. 1. — Tinajas Altas, Western Desert Tract. 



Fig. 2. — Campo, California, Pacific Coast Tract 122 



TEXT FIGUEES. 



Page. 



Fig. 1. — Diagram showing sections of Mexican Boundary Line 7 



2. — Distribution of trees on the west side of the Animas Mountains 92 



3. — Tayaasu anguiatum. a, Eight forefoot; b, right hindfoot 161 



4. — ^Tayassu anguiatum sonoriense. a, Skull, lateral view; h, dorsal 



view 163 



5. — Tayassu anguiatum sonoriense. a, Skull, ventral view; b, lower jaw, 



.seen from above 164 



6. — ^Tayassu anguiatum sonoriense. Skull, front view 165 



7. — Tayassu anguiatum sonoriense. Inner surface of ear 165 



8. — Tayassu anguiatum sonoriense. a. Eight hindfoot; 6, right forefoot. 165 



9. — Odocoileua americanus. a. Skull; 6, audital region 172 



10. — Tail of odocoileus couesi. a, Under surface; b, upper surface 176 



XI 



