70 



NATURAL RESOURCES SURVEY 



Valleys 



Dissect- I 

 ed edge j 

 of the) 

 "mesas" 



I 



Moun- 

 tains 



The mud flats of the Rio 



Grande 



The Cottonwood Forest 

 The Juncus Pepperweed 



Society (a meadow) 

 The irrigated fields 

 Acequia banks 

 Grassy meadows, poorly 

 represented along the 

 Rio Grande but well 

 developed below Aco- 

 ma and other valleys 

 Bigelovia Association 

 Ray less Golden-rod Soc. 

 Dalea scoparia Croton 

 Soc. (in very sandy 

 places) 

 Yucca Society, (also in 



sandy soil) 

 Sand Dunes 

 Bigelovia Hills 

 [ Hymenatherum Hills 

 f The grassy Steppe For- 

 mation (This includes 

 the lower "mesas", 

 j those free of trees. The 

 higher parts are in- 

 cluded in the rext) 

 f Cedar Association (Juni- 

 ; perus monosperma) 

 ; Opuntiaarborescens So- 

 ciety. 

 Pinon Association 



Box-elder Society 

 Pinus ponderosa Associa- 

 tion (Yellow Pine) 

 Oak Chaparral (on high 



slopes) 



Populus longifolia So- 

 ciety (In the canons) 

 Red Cedar Soc. (on tra- 

 vertine deposits along 

 streams) 



Meadows along moun- 

 tain streams 

 Meadows on high slopes 



Merriam classed this 

 as Lower Sonoran 

 but Cockerell and 

 others do not agree 

 with him but call 

 it a transitation 

 between the upper 

 and lower 



Upper Sonoran 



Transition Zone 



