3i8 The Ohio Naturalist. [Vol. VIII, No. 6' 



THE BEACH-SAXD PLAIX-HE ATH-FOREST SUCCESSION. 



This is the more common succession on the Cedar Point sand 

 plain where the habitat is of several years duration. It is 

 doubtful, if this succession were introduced onto the Bar Section, 

 that it could reach maturity. In che Dune Section the heath 

 and forest stages are essentially identical with the dunes and 

 blowouts and, as the former often merge imperceptibly into the 

 latcer two formations the discussion of these stages will be 

 taken up in connection with the discussion of the dune and 

 blowout vegetation. 



THE DUNE AND BLOWOUT SUCCESSIONS. 



Under the above heading may be included a number of second- 

 ary formations which, taken together, make up inost of the vege- 

 tation of the Dune Section of Cedar Point. As Moseley has 

 pointed out,^^ this part of the peninsula represents a portion of 

 the original mainland upon which has been heaped the loose 

 sand, coincident with the rise of the waters of the Lake. There 

 can be no doubt that the land was originally covered here with 

 forest, probably an Ulmus-Acer forest formation, which later 

 perhaps gave wav to marsh vegetation but upon which, still 

 later, has been heaped the loose sand bringing about conditions 

 suitable for the present dune and blowout formations. 



The Amniophila Fringing-Dune Formation. 



Along most of the Lake shore of the Dime Section the Drift 

 Beach extends up to a well-marked Amniophila fringing dune. 

 This species of grass has the ability to grow upwards for a number 

 of feet if continuously buried more deeply by accumulating sand 

 and as the sand accumulates around the ever higher obstruction 

 a gently sloping ridge is finally built up. The height of such a 

 dune or ridge is determined by the height to which the grass can 

 grow vertically, the amount of obstruction which it offers the 

 drifting sand, and, finally, the force of the wind which tends to 

 tear the dune down again. 



The structure of the Amniophila Fringing-Dune Formation[is 

 quite simple: 



Facies: Amniophila arenaria. 



Principal Species: Psilocybe amniophila. 



Secondary Species: 



Euphorbia poly goni folia, Andropogon scoparius, 



Artemisia caudata, Strophostyles helvola, 



Cakile edentula, Panicum virgatum, 



Salix interior. 



18. Moseley, E. L. 1. c. pp. 22()-2L':?. 



