128 BULLETIN 56, UNITED STATES NATIONAL MUSEUM, 



palo verde, and ironwood only occur on the granite hills about 

 Yuma. The cockle (Xanthium) and a coarse Gyperus cover sandy 

 banks; and, as the river broadens toward its mouth, vast savannas, 

 canebrakes, »nd tule and carrizo marches are encountered. From 

 what has been said it will be seen that the region has little that is 

 distinctively tropical in its flora, its most peculiar feature consisting 

 in the dense growth of willows strung with coyote melons and thickly 

 mixed with stout amaranths and tall hemp, making jungles almost as 

 difficult to penetrate as -the canebrakes. 



Station No. 69.— Left (east) bank of the Colorado Eiver, at 

 Monument No. 205, 859 kilometers (534 miles) west of the Kio 

 Grande. Altitude, 26 meters (85 feet). Frequent visits were made 

 to the bank of the Colorado by the writer ; and Mr. Holzner trapped 

 mammals there in March, 1894. 



Station No. 70. — Las Carpas, Colorado river bottom, Sonora, Mex- 

 ico, 24 kilometers (15 miles) south of Monument No. 205. Altitude, 

 about 20 meters (66 feet) . I camped there March 29 to 30, 1894. 



Station No. 71. — Cienega Well, Sonora, Mexico, 40 kilometers 

 (25 miles) south of Monument No. 205. The Colorado bottom is 

 many miles in width at this part and covered by* carrizo, cane, tule, 

 and other semiaquatic vegetation, with mesquites on the drier places 

 and willow and cottonwood beside the marshes and lagunas. I 

 camped there March 23 to 24, 1894. 



Station No. 72. — Colonia Diaz, Colorado Eiver, Sonora, Mexico, 

 48 kilometers (30 miles) south of Monument No. 205. This fertile 

 tract of the Colorado River bottom was visited by myself and an 

 Indian assistant March 29 and 30, 1894. The town was found to be 

 nearly deserted, only three houses being occupied by Mexicans at the 

 time of our visit. Indians burn off the carrizo marshes and stretches 

 of hemp and amaranth at this season, destroying much animal and 

 plant life. The savannas are covered with wing-leaf grass mixed 

 with patches of tule and triangular-stemmed bulrushes. 



Station No. 73.— Left (east) bank of the Colorado Eiver, oppo- 

 site the mouth of Hardy River, Sonora, Mexico. The Colorado is 

 salt at this place and subject to the ocean tides. My camp was lo- 

 cated on a marshy bank at the lowest point we were able to reach 

 with an escort wagon drawn by eight stout mules. In getting to it 

 we crossed the last ridges on which mesquites could exist, all beyond 

 being impassable if wet. Above these flats, which are inundated when 

 the water in the Colorado is high, and also by the high monthly tides, 

 we crossed the last ridges on which mesquites could exist, all beyond 

 being bare flats or green savannas. The tide creeks and broad bays 

 about our camp were swarming with waterfowl, which were nowhere 

 else seen in so great abundance. Pelicans, cormorants, geese, ducks, 



