PHYSIOGRAPHY AND SOILS. 



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mesquite and other timber is encroaching upon the prairies where 

 its natural spread is not held in check by agricultural development. 



Fig. 1. — Map of a part of the State of Texas, showing the territory covered and places 

 visited in connection with the plant-disease survey. 



The prevailing soils in this area except in the bottom lands are 

 stiff. Avaxy clays, generally with an impervious clay subsoil, and 



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