THE PEAT CLISTASE. 



385 



of the peat-moors, but apparently is no longer formed. In spite of the 

 calcareous subsoil Sphagnum peat is constantly formed anew in the moors. 

 The Phragmites-Cladium and Carex strida commimities furnish the material 

 for the formation of different kinds of grass-peat. The author has found also 

 two pronounced stmnp-layers in the peat-moors, containii^ for the most part 

 old forest remains. These are regarded as indicating interruptions in the 

 growth of the peat, and are identified with the boreal and sub-boreal periods of 

 Blytt. The first fell in the last part of the Ancylus period, the latter in the 

 lAtorina period. The moist Atlantic period opened the Ldtorina period, and 

 in the uppermost parts of peat-moors are to be found remains of the moist 

 sub-Atlantic period bedded upon the sub-boreal stump-layer. Finally, an 

 exhaustive account is given of the invasion and general development of the 

 vegetation. The latter is shown graphically in figure 40, while the geological 

 periods and the corresponding vegetations are found in the table at the bot- 

 tom of this page. 



Meny- Carex 



antnes atricta 



Forma- Fprm, 

 tjon> 



C.fXIi- 

 formjs 

 Fj 



Cladtum- Phrag- Schoenua 

 Form. mJtea nigricana 

 Forjn, Form. 



S. ferru- 



Carex 



panlcea 

 Form. 



Sphagnetom 

 carlcJisriMO 



Pinetoro 

 aphagnotizm 



Blrch-Ptne mtKed foreat 

 Fig. 40. — Adseres of the hydrosere in southern Sweden. After Semandei. 



