290 Annals of the Carnegie Museum, 



Mr. J. G. Sanders, of Washington, for having made tracings of these 

 maps and charts ; to Mr. George H. Fenkell, Engineer of the City- 

 Water Works of Erie, and to Mr. Andrew W. Shaw, Keeper of the 

 Presque Isle Light, for many courtesies, which added to the success 

 and pleasure of the work. For the lettering of the maps the author is 

 indebted to Mr. Sidney Prentice, to whom also are due many thanks 

 for suggestions and assistance in preparing the drawings and photo- 

 graphs, which, unless otherwise indicated, are the work of the author, 

 assisted by Mrs. O. E. Jennings. 



In matters pertaining to botanical nomenclature the author has en- 

 deavored to the best of his ability to keep this article thoroughly in 

 accord with recent discoveries and advances, while at the same time the 

 effort has been made to adhere consistently to the principle of priority 

 as maintained in the amended Philadelphia Code of Botanical Nomen- 

 clature, published in 1907. 



The Physiographic Origin of Presque Isle. 



Although the larger associations of plants, such as those of the 

 desert, the prairie, open forests, and dense forests, are to be correlated 

 with certain general climatic conditions, it is no less evident that the 

 smaller associations of more restricted areas, such as societies and for- 

 mations, and the sequence of formations in a succession, are to be 

 correlated with local physiographic conditions. 



It is thus evident that the best knowledge of the ecological associa- 

 tions of a locality is only to be obtained in connection with physio- 

 graphic studies, including such factors as the composition of the 

 soil, physical and chemical ; moisture of the soil ; topography ; etc. 

 Cowles "' has been one of the first of a rapidly widening circle of 

 ecologists in America to carry on extended studies of the vegetation 

 of a region from the standpoint of "physiographic ecology," /. e., 

 considering the vegetation of a region as the natural expression of its 

 physiography. 



The topography and development of lake-shores has been the subject 

 of very careful investigation,^ especially in the case of the Great 



■* Cowles, II. C. " The Ecological Relations of the Vegetation of the Sand Dunes 

 of Lake Michigan." Bot. Gaz., 27 : 95-117, 167-202, 281-308, and 361-391, Feb- 

 ruary, March, April, and May, 1899. 



••Gilbert, G. K. "Topographic Features of Lake Shores." U. S. Geol. Surv., 

 Ann. Rpt., 5 : 69-123, 1884. And Russell, I. C. " Lakes of North America," 1895. 



