BIG SPRING PRAIRIE. O 



eastern prairie is only an intermediate formation be- 

 tween the marsh and the forest formation. It is simply 

 a question of time. The observed facts corroborate this. 

 As it is difficult adequately to define tree, but much 

 easier to define deciduous tree, still easier to define 

 Cottonwood tree, and easiest to define Populus grandi- 

 dentata; so it is difficult to announce principles, or 

 elaborate a statement of facts which shall fully apply to 

 all prairies in all conceivable localities, and under their 

 various natural conditions, but easier to apply the same 

 to the eastern prairie, still easier to the Ohio prairie, 

 and easiest to apply certain well-defined principles, and 

 give a statement of observed facts in regard to Big 

 Spring Prairie. The last named task shall be ours 

 chiefly in the following article. In accordance with 

 the above, our investigations have been conducted 

 along the following lines. 



(i) Geological formations surrounding prairie, and 

 the characteristic vegetation of same. 



(2) Past condition of prairie, especially since 1832, in 

 which year the Big Spring Indian Reservation was 

 thrown open to settlement. 



(3) The drainage of prairie, past and present, and its 

 effect upon general level of same and also upon the 

 character of the vegetation. 



(4) The lagging behind of effects, as shown by the 

 observed facts that plants cling for a time to a local- 

 ity after the conditions have changed, in this instance 

 from the hydrophytic to the mesophytic. 



(5) The nature of the soil in the various portions and 

 the characteristic vegetation of same. 



(6) Tree introduction or encroachment upon prairie, 

 the order and cause. 



(7) The prairie under cultivation. 



