226 JJfLLHTix 89 



having knoAvledge of conditions on the Mesa. Careful studies were 

 made of the citrus plantings and of other crops and vegetation now 

 growing there, and inquiries were made concerning the past his- 

 tory of these crops, particularly the old citrus grove known as the 

 Blaisdell Orchard. Units A and B of the project, as surveyed by 

 the Reclamation Service, were inspected by several automobile and 

 foot trif)s. Soil samples representative of the different soil phases 

 were taken for chemical and mechanical analysis, and for physical 

 tests and pot cultures. Fruit samples were obtained for physical 

 and chemical analysis, and for comparison with similar fruits from 

 Florida and California. 



TOPOGRAPHY OF THE YUMA MESA 



The Yuma Mesa rises abruptly about 100 feet a'bove the valley 

 of the Colorado River and stretches to the mountains on the east, 

 sloping gently southward into Mexico. Depressions, commonly 

 spoken of as pot holes, are found at a few places. The entire region, 

 probably, was once the floor of the upper end of the Gulf of Cali- 



Fig. 2. — General view on the Yunia Mesa 



fornia, which accounts for the prevalence of sands. Frequent 

 draws lead from the mesa to the valley below making the margin 

 quite rough. The great body of the Mesa, however, is level and 

 may be brought under cultivation with little expense for grading 

 creosote bushes. A few dunes, too large for leveling, occur, but 

 other than the leveling of small sand dunes, collected about the 



