FRESH-WATER SWAMPS 



499 



horizontal section there will be a marked change in the peats filling 

 a single basin. Such differences are frequently observed in single 

 basins, and also between adjoining basins, where slight differences 

 in the physical characters may bring about marked variation in the 

 result. The range of variation is enormously increased under the 

 influence of fluctuating climatic conditions such as nearly every 

 country experiences sooner or later. 



An inverted order of superposition may result from a raising 

 of the water level, often due to the growth of a retaining rim of peat, 



Telmalic or 

 SetnihrreslTial 

 Terrestrial 



1. Younger SphagnetaTn Peat 

 ' 5cheach£erieto- Sphagneta-m Peat 

 ■2.'|BoLLTidarij horizon •• Lrlophoretam Peat 



[ (E.vag'iTiatiiTn caLlanetaTTi Peat) 

 3 Older SphagTietam Peat 



JScheuchzerietuTa Peat.CarLceto-SphagnetnTD o 

 '''I ErLophoretum Peat (E.vatjlTiQtum etc.) 



5 I Pmeto-BetaletuniPeat;LQL|erof pine stixTTips LTi upperJTerrestrLoi 

 L pQrt,and beneath that of ten lor Z barni surtoces 

 ^Inetam Peat 

 z Phraqinltetam Peat 



Semiterrcslr, 



■^CTTiiterrt^tTial 



Telftiatic or 

 ScTDitfrrctnol. 



SemiterrestTial 

 lei mat i" 





s Peat mad 



^ Liver- colored mud (Lebbermadde) 



'0 Lime mud 



"• Clay TTiLid 



'^ DilauiaL bottoTn 



Fig. 114. Section through a North German peat bog, showing the succession 

 of strata. (After Ramann.) 



or through sinking of a floating mat. A floating mat is composed of 

 interlacing roots and stolons of hygrophytes, above which form 

 semiterrestrial or even oligotrophic peats. When the weight be- 

 comes too great, the floating mat sinks with its load, and the meso- 

 trophic and eutrophic deposits will again form. Thus a layer of 

 oligotrophic peats may occur interpolated between layers of eutro- 

 phic peat deposits. 



A section seven meters deep through a North German peat 

 series in which the peat- forming processes had come to an end gave 

 the succession shown in the above diagram (Fig. 114). 



