INTRODUCTION. 



For teu years the Biological Survey (and its predecessor, the Divi- 

 sion of Ornithology and Mammalogj^) has had small parties in the 

 field traversing the public domain for the purpose of studying the 

 geograx^hic distribution of our native land animals and plants and 

 mapping the boundaries of the areas they inhabit. The present 

 report is intended to explain the relations of this work to practical 

 agriculture and to show the results thus far attained — it does not 

 deal with other investigations carried on by the Survey. 



It was early learned that North America is divisible into seven 

 transcontinental belts or life zones and a much larger number of 

 minor areas or faunas, each characterized by particular associations 

 of animals and plants. It was then suspected that these same zones 

 and areas, up to the northern limit of profitable agriculture, are 

 adapted to the needs of particular kinds or varieties of cultivated 

 crops, and this has since been fully established. When, therefore, 

 the natural life zones and areas, seeminglj^ of interest only to the 

 naturalist, were found to be natural crop belts and areas, they became 

 at once of the highest importance to the agriculturist. A map show- 

 ing their position and boundaries, so far as ascertained at the close 

 of the field season of 1897, accompanies this rei3ort, and lists of the 

 more important crops of each belt and its ]3rincipal subdivisions are 

 here for the first time published. The matter relating to the native 

 animals and plants has been reduced to a fragmentary outline, for the 

 reason that this branch of the subject is of comparatively little inter- 

 est to the farmer and fruit grower. 



Under the head 'Important crops,' and in the corresponding 'Crop 

 tables ' at the end of the report, great care has been taken to make 

 the lists accurate and trustworthy as far as tliey go. One of the chief 

 difficulties encountered is that nearly all of the published matter 

 relating to the distribution of crops is arranged by political divisions, 

 as States or counties, and consequently is of little assistance as a 

 guide to climatic or zone requirements. Another difficulty is the 

 over sanguine attitude of many fruit growers and horticultural socie- 

 ties, particularly in the West, where innumerable varieties are re- 

 ported as succeeding in places where they liave not been tested a 

 sufficient length of time. The intention in the present report has 

 been to omit doubtful records, and since reliable information from 

 specific localities of known zone position is exceedingly scarce, it is 



