LETTER OF TRANSMITTAL. 



IJ. S. Department op Agriculture, 



Division op Biological Survey, 



Washington, D. C, June 26, 1898. 

 Sir: I have the honor to transmit herewith, for publication as Bul- 

 letin No. 11 of the Biological Survey, a report on 'The Geographic Dis- 

 tribution of Cereals in North America,' by Prof. C. S. Plumb, the result 

 of an investigation made under an authorization of the Secretary of 

 Agriculture under date of January 2, 1897. The object of the inquiry 

 was to ascertain the areas in which the more important varieties of 

 certain cereals were cultivated and to determine how far the distribu- 

 tion of cereals accords with the boundaries of the life zones as mapped 

 by the Biological Survey. 



This report was received a year ago, but its publication has been 

 delayed in order that it might be accompanied by a revised map of the 

 life zones, necessary to its proper comprehension. 

 EespectfuUy, 



C. Hart Merriam, 



Chief, Biological Survey. 

 Hon. James Wilson, 



Secretary of Agriculture. 



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