218 NATUEAL HISTOKY BULLETIN 



The following writers gave expression to more or less pro- 

 nounced views favoring fire as the great cause of the prairie: 

 Wells (1818), Ellsworth (1837), Fendler (1866), White (1868, 

 1870, 1871), Sternberg (1869), Allen (1870, 1871), Winchell 

 (1880), Kedway (1894), Gaskill (1905) and Hopkins (1910), 

 while the following at least mentioned it, or regarded is as an 

 accessory or secondary cause: Nutt (1833) with tornadoes, West- 

 ern Monthly Magazine (1836), reprint (1838), Phillips (1844) 

 with wind. Swallow (1879), Aughey (1880), Alexander Winch- 

 ell (1886, 1890, 1894), McGee (1891), Shaler (1892, 1896), 

 Macbride (1894, 1896, 1899, 1900), conditioned on moisture, 

 Upham (1895), Powell (1896), Gow (1899), Davis (1900), 

 Condra (1906), Cook (1908), Baker (1908), and the writer 

 (1900, 1911). The references to burning of prairies for pasture 

 for the bison were mentioned under the preceding head. 



A few authors opposed the fire-theory as a fundamental cause, 

 usually in connection with the advocacy of some other cause. 

 Among these may be mentioned: Whitney (1858, 1876), Alex- 

 ander Winchell (1876), Tarr (1896) and Harvey (1908). 

 Bourne (1820) considered fire as the cause of the barrens but 

 not the general prairies. 



The facts which have been regarded as supporting the fire- 

 theory may be briefly summarized as follows : 



1. Prairie fires were once extensive, and destructive to aerial 

 parts of plants. 



2. Prairies appeared chiefly in drier situations where vege- 

 tation would burn more readily, and forests were found mostly 

 along streams. 



3. The small, stunted bur-oak shrubs common in the western 

 part of the state have large bench-roots. It was assumed that 

 the tops were periodically burned away and that the large root 

 sent up new shoots, thus forming low shrubs. 



While there can be no question as to the extent and destruc- 

 tiveness of prairie fires, they must be looked upon, as stated, 

 rather as an effect than a cause, for nowhere in Iowa or adja- 

 cent territory has there been any marked general encroachment 

 of the forest on the prairie M^hen the fires ceased. In much of 

 the territory the rapid settlement and extensive cultivation of 



