150 
Ohio Biological Survey 
clover (Melilotus alba), and wire grass (Poa compressa) are scattered 
over the almost bare bank. At the top of the bluff are red elm (Ulmus 
fidva), hop hornbeam (Ostrya virginiana), locust (Robinia Pseudo-Acac¬ 
ia), red-fruited thorn (Crataegus mollis), blue ash (Fraxinus quadrangu- 
lata), and chestnut oak (Quercus Muhlcnbergii). Toward the upper end 
of the bluff, these are seen advancing down the slopes. Fig. 22 shows, in 
the left foreground, the upper end of an undercut bank, and in the dis¬ 
tance, a higher and barer bluff. 
Fig. 22 . Muddy creek under-cutting its banks; scattered herbaceous plants on the 
bluffs, trees advancing onto the upper end. 
As conditions become less severe, and a little soil is formed, a number 
of other trees appear, among which are white oak (Quercus alba), hack- 
berry (Celtis occidentalis), redbud (Cercis canadensis), basswood (Tilia 
amcricana), and sometimes red cedar (Juniperus virginiana), red oak 
(Quercus rubra), bur oak (Quercus macrocarpa), and sugar maple (Acer 
saccharum). Many of the trees which have been mentioned are of low 
growth, and it is not long before the oaks reach above them. 
