28 



GENERAL HISTORICAL SUMMARY. 



A. The beach. 



1. The lower beach. 



2. The middle beach. 



3. The upper beach. 



4. Fossil beaches. 



B. Theembryonicorstationarybeachdunes. 



1. Dunes of rapid growth (primary em- 



bryonic dunes). 



2. Dunes of slow growth (secondary em- 



bryonic dunes). 



regarded "not as a changeless landscape feature, but rather as a panorama, 

 never twice alike." The author concluded that "the ecologist must study 

 the order of succession of the plant societies in the development of a region, 

 and that he must endeavor to discover the laws which govern the panoramic 

 changes. Ecology is, therefore, a study in dynamics." The ecological fac- 

 tors of the dunes were considered under the heads: (1) light and heat, (2) wind, 

 (3) soil, (4) water, (5) other factors. The plant societies and their develop- 

 mental relations were treated in full under the following captions: 



C. The active or wandering dunes; the dime 

 complex. 



1. Transformation of stationary into 

 wandering dunes. 



2. Physical and biological features of the 

 dime complex. 



3. Encroachment on preexisting plant 

 societies. 



4. Capture of the dune complex by vege- 

 tation. 



D. The established dunes. 



1. The basswood-maple series. 



2. The evergreen series. 



3. The oak dunes. 



An abstract of the account of the various stages will be found in Chapter X. 



Cowles, 1901. — Cowles's work (1901: 73) upon the physiographic ecology of 

 Chicago and vicinity stands out as a landmark in the developmental study of 

 vegetation. It forced the recognition of physiography as the most striking 

 cause of vegetation changes, and the use of the term "physiographic ecology" 

 constantly challenged the attention of students to the attractiveness and sig- 

 nificance of successional studies. Cowles deserves great credit at the hands 

 of ecologists for his early and consistent championing of the cause of develop- 

 ment in vegetation. Even though physiography can not yield a complete 

 picture of succession, as Cowles himself recognized (1901: 81; 1911: 168), its 

 processes are so striking and interesting, and its action as an initial cause of 

 development so universal and decisive, that it must always receive a large 

 share of attention from students of succession. The author's conclusions as 

 to progression and regression are considered in detail in Chapter VIII, while 

 an account of the concrete results in the various seres is given in Chapter X. 

 As a consequence, the following outline will suflBce to afford a general idea of 

 the work, and to indicate its basic nature. 



I. The content and scope of physiographic 

 ecology. 

 II. The plant societies. 

 A. The inland group. 



1. The river series. 



(1) The ravine. 



(2) The river-bluflf. 



(3) The flood-plain. 



2. The pond-swamp-prairie series. 



(1) The pond. 



(2) The undrained swamp. 



(3) The prairie. 



II. The plant societies — Continued. 

 3. The upland series. 



(1) The rock hill. 



(2) The clay hill. 



(3) The sand hill. 

 B. The coastal group. 



1. The lake-bluff series. 



2. The beach-dune-sandhill series. 



(1) The beach. 



(2) The embryonic or stationary 



beach areas. 



(3) The active or wandering dunes; 

 the dune complex. 



Summary and conclusion. 



