180 



seldom extended beyond the line of bluffs, and was composed 

 quite generally of the more hydrophytic species of the river 

 bottoms. On the east side it frequently extended out upon the 

 uplands to a considerable distance, and was there composed of 

 the more xerophytic species, especially the oaks and hickories. 

 A careful estimate of the forest areas in Champaign County, 

 based on the original land surveys, indicates that about 68 per 

 cent, was located at the east and north, and only 32 per cent, at 

 the west or south. 



Closely allied to this effect of prairie fires is the shape of the 

 extremities of the forest farthest upstream. These were origi- 

 nally not narrow tongues, composed of permobile species, but 

 were broadly rounded in shape, and characterized chiefly by the 

 less mobile species, as the oaks and hickories. Along the three 

 rivers which rise in Champaign County, it is never more 

 than two miles from the end of the forest to mesophytlc 

 associations with basswood, papaw, and sugar maple. On these 

 three rivers, also, the forests extend upstream just as far as there 

 is a marked contrast between upland and flood plain. Beyond, 

 where base-leveling has not been prominent, the prairies were 

 continuous on both sides of the stream. Since in general the 

 mobile species migrate farther up the streams at present, it may 

 be concluded that the former extremities of the forest belts 

 have been destroyed by fires. 



IV. The belief of the writer that the forests in central Illinois, 

 and probably in many other parts of the Middle West, formerly 

 occupied a much greater area than at present has already been 

 stated. It seems probable that these forest belts extended up 

 the streams a little farther toward their sources than at present; 

 that their width was greater; and that there were also extensive 

 forests developed along the more rugged moraines. The evidence 

 for the latter statement demands some explanation. 



There are in central Illinois even at the present time various 

 places where forests are developed on the moraines, independ- 

 ently of streams. Such is the case on the Bloomington moraine 

 between Bloomington and Peoria. On other moraines now 

 unforested there are frequently various species of plants which 



