182 
Ohio Biological Survey 
It is only along the crests of narrow divides, or upon unusually steep 
slopes, that the beech forest is superseded by a xero-mesophytic or mixed 
forest. Such areas are, however, always small. 
The prevalent forest of dissected areas is a mesophytic forest inter- 
Fig. 41. View over the Norwood trough from top of valley slopes. Beech is dom¬ 
inant in all the wooded areas; the oak (Quercus muhlenbergii) in the fore¬ 
ground belongs to the slopes. 
mediate in character between the pre-erosion and erosion types, but most 
closely approaching the latter. Its development has been more rapid, 
with consequent greater simplicity of the forest, than has that of the 
erosion climax forest previously discussed, but it nevertheless represents 
an erosion type. 
2. Upper Mill creek valley area 
The valley .—A part of the broad flat valley of upper Mill creek is 
covered with recent alluvium, and belongs to the flood plain area. In 
the rest of the valley, glacial deposits are at the surface. Nothing of the 
original vegetation of this part remains. It is all farm land. 
