133 



THE FOREST FORMATION 



Mixed Forest 

 Assoc. 



Black Oak 

 Assoc. 



/1\ 



Swamp 

 Assoc. 



THE SWAMP FORMATION 



Polytrichum 



Assoc. Sallx 

 Assoc. 



Deposit <: Blowsand < Basin Windward Slope 



Assoc. ^ Assoc. > Assoc- Assoc. 



Panicum pseudopubescens 

 Assoc. 



Bunch Grass 

 Assoc. 



THE PRAIRIE 



THE PRAIRIE FORMATION 



PROVINCE 



THE BLOWOUT FORMATION 



Fig. 6. DiafTram showing- tlie plant associations of the inland sand deposits of Illinois, 

 and the principal su>.cessions Isetween them. 



