MASSACHUSETTS PEAT LANDS 33 



ent habitat. But the conquest of some of the former lakes, ponds, 

 and inundated depressions along rivers and the coast is still going 

 on and many of the isolated plant associations still survive as the 

 remnants of a more northern type of plant succession. Coastal 

 cedar swamps and river marshes are quite suggestive of this fact, 

 for the cranberry sphagnum type of bog meadow described else- 

 where as one of the members in the classification of peat lands (Ohio 

 Geological Survey, Bull. 16, 1912), is of frequent occurrence as the 

 ground mat where boreal, certain austral, and even several maritime 

 plants may find conditions for growth and establishment. There 

 is abundant evidence tending to show that southern plants seem to 

 be gaining the ascendancy and that wherever suitable changes in 

 drainage and weathering ensue, spruce, fir, tamarack, pine^ and 

 cedar become replaced largely if not entirely. Red maple, elm, 

 ash, and others are contributing more and more to the increasing 

 complexity of peat materials. 



Very much of what we wish to know about the composition of 

 peat materials, its variations and the effects of these upon crops 

 depends, therefore, on the detailed study of profile sections of a peat 

 basin; they recapitulate, so to speak, the history of its formation. 

 There is a growing recognition of the injustice and the unbusiness- 

 like character of treating all kinds of essentially different peat 

 materials as being equal in quality and cropping value. It requires 

 no argument to show that peat materials are of different composi- 

 tion and have different agricultural and industrial possibilities, but 

 it demands considerable information and investigation to establish 

 these differences scientifically and to show in what manner their 

 agricultural and economic value is not the same. The physical 

 constitution varies greatly according to locality and topographic 

 features and even in the same field; a recognition of the controlling 

 or modifying factors would emphasize to those using peat land the 

 inherent limitations of the materials. This point is brought out 

 clearly from any series of peat samples obtained in a profile sound- 

 ing operation. 



The lowest layer is frequently a plastic amorphous peat derived 

 in the main from aquatic forms of plant and animal life (diatoms 

 etc.), and from disintegrating floating organic debris of the marginal 

 vegetation. When the accumulation of this material has reached 



