Bui. 211, U. S. Dept. of Agriculture. 



Plate I. 



Fig. 1.— View in the Northeastern Part of New Mexico, Showing the Topog- 

 raphy as Affected by Lava Sheets. 



Fig. 2.— A Typical Bolson, or Basinlike Mesa, in the Southern Part of New 

 Mexico, Showing the Shrubby Association on the Gravelly Portions of 

 Such an Area. 



