3 22 
The Ohio Naturalist. 
[Vol. VIII, No. 6, 
If the shore line of the Dune Section were advancing towards 
the Lake there would in all probability be a corresponding ad¬ 
vance of the Quercus velutina-imhricaria Forest Formation over 
the dunes towards the east but, as conditions are at present, 
there! seems to be only in a few places any real advance made by 
the oak forest and, practically, a state of equilibrium may be 
said to exist as to this phase of the question. 
Fig 10 . A dune controlled by the Prunus virginiana Consocies of the 
Prunus-Rhus Dune Thicket Formation. Note secondary species: Juni- 
perus virginiana , Asclepias syriaca, Panicum virgatum. In blowout sur¬ 
rounding dune note Panicum virgatum, Salix interior. This dune appears 
in distance in left third of preceding illustration. 
Towards the northern portion of the Dune Section the grass 
dune formations are followed by a formation consisting of ever¬ 
green shrubs with northern phytogeographieal relationships, this 
formation being termed: 
The Arctostaphylos-Juniperus Heath Formation. 
This formation, once established on a dune, brings about more 
stable conditions than does the Prunus-Rhus Thicket Formation. 
The vegetation being evergreen the winter winds are obstructed 
much more than is the case with a deciduous dune vegetation 
and not only are more stable conditions brought about but more 
sand is deposited by the wind. The structure of this formation 
is as follows: 
