BIG SPRING PRAIRIE. 95 



BRIEF SUMMARY OF FACTS IN REGARD TO BIG SPRING 



PRAIRIE 



1. Big Spring Prairie is a peculiar marsh area, 

 when compared with other drained marshes of the 

 state. 



2. This prairie was most probably a portion of a 

 preglacial drainage valley, and without doubt, a post 

 glacial lake. 



3. The water content and capacity of the soil of 

 this prairie is above the average. This fact accounts 

 for the striking lagging behind of effects in regard to 

 plant life. 



4. The low temperature of the soil water ac- 

 counts for this prairie's marking the southern limit for 

 the range of Betula pumila in Ohio. 



5. Artificial drainage has considerably lowered 

 the general level of the prairie. Occasional deepening 

 of the ditches will be needed on this account. 



In the drainage of other marsh areas, this lowering 

 of the general level must be taken into account. 

 There must be sufficient fall in the outlet ditches, not 

 only for proper immediate drainage but for drainage 

 in the future when the soil has settled. 



6. Few ridge species of plants ever gain a foothold 

 upon the prairie. 



7. Direction of prevailing winds in connection 

 with location of any given area, as along eastern or 

 western borders of same; determines largely the num- 

 ber of species upon it. 



8. A dense sod tends to prevent the encroachment 

 of other forms of vegetation, especially tree seedlings. 

 It is not so eflfective against shrubs as is evidenced by 

 the heath formations. 



9. Burning of soil causes reversions of plant so- 

 cieties in the depressions; on others it leads to estab- 

 lishment of forests, This is especially true if the 



