37 



within the state, so also has Barrows ('lo) shown the influence of the 

 forests and prairie upon the state's development. While the influence 

 of the soil upon the animal life of the state is not so well known or es- 

 tablished, the influence of prairie and forest upon the animals is univer- 

 sally recognized, even though the subject has been given relatively 

 little study by naturalists. 



A third leading agency is the influence of man, who has trans- 

 formed the prairie and forest to make his own habitat. There are thus 

 recognized in the Charleston region three primary environmental in- 

 fluences : first, the relative fertility of the soil (this depending on the 

 geological history) ; second, the kind of vegetable covering, whether 

 prairie or forest (this probably depending largely on climatic condi- 

 tions) ; and third, the agency of man. The general background of the 

 Charleston region, then, ecologically considered, depends on the com- 

 bined influence of five primary and secondary agencies, four of which 

 we may call natural and one artificial. All these are different in kind 

 and so independent that they tend toward different equilibria or dif- 

 ferent systems of unity. Two of these are due to differences in the 

 soil, two others to the character of the vegetation (whether prairie or 

 forest), and the fifth, or artificial one, is due to man. Though the 

 present report does not undertake to include all the problems centered 

 here, as any complete study would, it is desirable to see the relation of 

 our special study to the general problems of the region as a whole. 



The undulating plain about Charleston, formed as a terminal mo- 

 raine, is broken along the small streams by ravines, which have cut a 

 few hundred feet below the general level of the region as they ap- 

 proached the larger drainage lines. The main drainage feature is the 

 Embarras River, which flows southwest about two to three miles east 

 of Charleston, in a narrow valley partly cut in rock. The wooded 

 areas are mainly near the streams ; the remainder of the area is under 

 intensive cultivation. 



During the preliminary examination of the region, which was made 

 to aid in selecting representative areag for study, it soon became evi- 

 dent that the only samples of prairie which could give any adequate 

 idea of the original conditions were those found along the different 

 railway rights-of-way. Other situations, vastly inferior to these and 

 yet a valuable aid in the determination of the original boundaries of 

 the prairies, were the small patches or strips along the country roads. 

 Most of the patches of prairie along the railway tracks represent the 

 "black soil" type of prairie, which is extensively developed in this part 

 of the state upon the "brown silt loam" soil" (see Hopkins and Pettit, 

 '08 : 224-231 ). Much of the region studied was originally wet prairie 



