April, 1908.] 
The Vegetation of Cedar Point. 
297 
f—The Cephalanthus-Cornus Thicket Formation, 
g—The Rhus hirta Thicket Formation, 
h—The Ulmus-Acer Forest Formation. 
(The Anomalous Ailanthus Forest Formation). 
THE COTTOXWOOD BAR-RIDGE-THICKET-FOREST SUCCESSIOX. 
As Prof. Moseley has so well shown, the terminal portion of 
Cedar Point, termed the Ridge Section, consists mainly of a series 
of sand ridges initiated by northeast gales during times of high 
water in Lake Erie, and subsequently built up to their present 
dimensions by the combined action of wind and vegetation in 
accumulating the loose beach sand. The approximate dates of 
formation of the ridges are shown to run consecutively from about 
1429 a. d. for the oldest ridge, on the Bay side of the peninsula, 
to 1899 for the youngest ridge along the Lake front. 
Beginning, therefore, with the present Lake Erie beach of 
the Ridge Section, the vegetation may be discussed from the 
developmental standpoint from the youngest to the older stages 
of the succession, the various stages being found in connection 
with similar physiographic units (sand ridges and intervening 
depressions) of consecutively older formation. 
During a northeast gale, with high water in the Lake, the 
loose beach sand may be piled up into a bar which, upon the sub¬ 
sidence of the waves, will be left more or less permanently above 
the ordinary water level. Behind this bar there will be a more 
or less completely segregated lagoon. Into such a beach lagoon 
there will be blown during late spring many willow and cotton¬ 
wood disseminules, which, floating upon the surface of the water, 
will soon be deposited and buried in the loose, wet sand which 
rapidly accumulates around the banks of the newly formed 
lagoon. Here the disseminules will sprout and the lagoon will 
soon be bordered by a zone of little cottonwoods and willows. 
The lagoon may be so narrow as to be completely filled up by 
the drifting sand before other vegetation may be able to estab¬ 
lish itself, or, if the lagoon be wider, other vegetation may become 
established only to be later buried under the sand and killed. 
In either case, however, a sand rigde has been initiated by the 
establishment of the zone of cottonwoods and willows. 
With the growth of the cottonwoods and willows there is 
offered an obstruction to the drifting sand, the height of the 
obstruction by its continued vertical growth tending to build 
the ridge ever higher. Cottonwoods will continue to grow 
vigorously under such conditions, providing the tops of the 
plants are not entirely buried. On Presque Isle the writer found 
cottonwoods buried to a depth of nearly 30 feet and still vigor¬ 
ously growing. As the lower branches of the tree become buried 
in the sand they die, although for a long time serving the purpose 
