148 MICHIGAN SURVEY, 1908. 



place, the dominance of the biotic formation is most complete. This 

 may be considered a geographic or environmental optimum. This, in 

 general, implies complete succession and the dominance of the climax 

 formation. 



6. From the standpoint of causes and proeesses, the succession of 

 societies and formations is the expression or result of the environ- 

 mental process moving toward an equilibrium. 



7. The lack of a uniform rate of succession throughout large areas 

 is the rule, on account of the slowness with which extreme conditions 

 are transformed into those of the average. 



8. The slowly changing extreme conditions tend to preserve many 

 of the most important early stages of conditions and succession; hence 

 the utility of these belated changes in validating succession as deter- 

 mined by the comparative method. 



9. Other things being equal, the slower the succession the greater 

 the chances for variation in the details and composition of the societies. 



10. The formation or climax society is only the most conspicuous 

 case of convergence, reached by all routes and successions, at a given 

 environmental center. 



11. The succession of societies within a formation is liable to be 

 more stable in its main features than the comiposition of its societies. 

 Probably the general features of such a succession most nearly ap- 

 proximate that which the region passed through in the development 

 of the formation. Adams, '05, p. 67. 



12. Formations of different geographic centers will vary in their 

 dominan-t dynamic tendencies, yet open (unforested) formations will 

 have certain features in common, as will also forest formations. Thus, 

 not only will the compositions of the societies vary, but also the climax 

 formations and their dynamic trends. 



13. The stability of the climax environmental factors and their biotic 

 formations is only relative. They may themselves migrate or change 

 by a progressive succession in the direction of the dominant environ- 

 mental trend. This migration involves a true succession, as is well 

 illustrated by changes and successions attending the Glacial influences 

 and the elevation of the Coastal Plain of the United States. (Of. Adams, 

 '05). 



14. The stability of dominance is due ta a complete biotic and 

 environmental adjustment brought about by the repeated selections of 

 the preceding succession and resulting in a "pure culture." Dominance 

 may be likened to the static social condition of China or to a monopoly. 



15. Succession is a form of complete or entire environmental selec- 

 tion, certain species or associations receiving an environmental ap- 

 proval while others are excluded. This is a particular and extensive 

 form of natural selection. Successional selection in its broadest ecolo- 

 gical aspect includes the evolution of the organisms, particularly as 

 members of associations in their most intimate environment. 



10. Any association not a climax is in unstable equilibrium and in a 

 condition unfavorable to its permanence. The climax society is in a 

 state of biotic and environmental equilibrium. (Cf. Warming, No. 6 

 and Clements V; also cf. No. 13, 14). 



