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THE AMERICAN NATURALIST. [Vol. XXXV II. 



place the development of these formations and their relation to 

 certain plant-communities will be treated. 



Japetus Steenstrup of Copenhagen was the first to begin the 

 difficult task of identifying the organic remains in peat bogs and 

 similar deposits. After him Axel Blytt of Christiania, A. G. 

 Nathorst and Gunnar Andersson of Stockholm, Rutger Sernander 

 and Henrik Munthe of Upsala have been the principal workers 

 in this field. Many pupils of Andersson and Sernander have in 

 later years pursued the study in Germany, Russia and other 

 countries, and the literature on the subject is rapidly increasing. 



The first paper on the method of examining fossil plants in 

 postglacial deposits was published by Andersson in 1892. 1 

 Improvements on his method were made known in 1892, 1893 

 and 1896. 2 Munthe gave (1894) a detailed account of biologi- 

 cal investigation of clays,3 and Professor G. Lagerheim 4 recently 

 ('02) related some new experiences with regard to the technique 

 of telmatological research. 



All these papers are in the Swedish language and the writer 

 thinks he is justified in bringing the methods in question under 

 the notice of American paleobotanists and ph\ togeographers, as 



logicaHestimony is likely to find adherents in the United States 

 and Canada, where postglacial deposits, so widely distributed 

 and covering immense areas, offer special advantages for this 

 line of research. 



The principal kinds of recent deposits in which we meet with 



lation of partially decomposed organic matter has been the most 

 important agent in their construction. 



When this process of decomposition is proceeding in presence 



