ROWLEE: RELATION OF MARL PONDS AND PEAT BOGS 411 



decidedly hard, that is, it is impregnated with Hme while the water of 

 peat bogs is soft, that is, it is not alkaline in its reaction. 



In a series of careful studies Davis has shown that marl is com- 

 posed mainly of the remains of the alga Chara. Chara thrives in 

 hard water and its cell walls are impregnated with calcium carbonate. 

 In many marl ponds a complete transition from the living Chara to 

 characteristic marl can be seen. Since Chara grows submerged and 

 the principal bog plants grow emerged it is evident why there is filling 

 at the shore in the one and in all parts of the pond in the other. 



In sounding many peat bogs in western New York, the writer was 

 somewhat surprised to find many of them underlayed with marl. 



Fig. I. Marl bog, northeast side of Lowry's Pond, West Junius, Seneca Co., 

 N. Y. Species of sedges the dominant vegetation form. 



The assumption had been that the alkaUne or nonalkaline character 

 of the water originally filling the depressions determined whether bog 

 vegetation or marl pond vegetation would develop in it. Is it possible 

 that a pond might be alkaline during one stage of its existence and 

 then become non-alkaline in a later stage? An affirmative conclusion 

 seems inevitable. 



It is Dachnowski's view that there are changes in the vertical or 

 historical succession in the bogs, for he says: "While working on the 

 ecology of ravines near Ann Arbor, Michigan, I became convinced 

 that the reactions of plants on their habitat were equally as great and 

 profound, in some cases, as the influence of edaphic and climatic 



