IMPORTAITT TYPES OF PEAT MATERTAI*. 33 



Except in a few Nortliern Stiites and in Canada the built-up layers 

 of bog-moss peat are rarely of great thickness or purity in plant 

 oouAposition. Other peat- forming plants which usually accompany 

 sphagnum mosses are the cranberry {Vaccinium spp.), sundew 

 (/^rcsY'n^spp.), arrow grass {S€heuchzerlas\).) ^itoiton grass {Erio'ph- 

 orum spp.), Rynclwuiyora spp.. Menydunthes sp,, various species of 

 sedge (Carex), and others (5). 



The rarity of S5phagnum peat is noteworthy and, together with 

 the i-ather restricted occurrence at the present day of "moss" bogs 

 as compared with sedge or "gTass" bogs and "heath" bogs, is in- 

 tei^sting, since sphagnum mosses are by many considered to be the 

 starting point and the type plant association of peat deposits. 



Considerable work has been done upon the physical and chemical 

 features of this type of peat material, some of which has been sum- 

 marized in Tables I and II. Other correlative phenomena have 

 been discussed in a previous publication (o, p. 386-392). 



ARliOW-GRASS TYPK. 



" Scheuchzeria peat," '• Beisentorf." 



t'OTTON-GKASS TYPE. 



" Eriophorum peat," " Wollgrasstorf." 



These two types are generally a composite in the peat accumu- 

 lations of this country. The plant remains appear to be rarely 

 of the thickness of accumulation or homogeneity in composition 

 recorded for European deposits. They are derived from bog plants 

 which associate with or follow closely a zone of the sphagnum-cran- 

 berry stage of bogs in oui- northern peat deposits. 



The peat material is rusty to reddish brown, rather coarsely 

 fibrous from plant remains, such as roots, rootlets, leaf bases, and 

 leaf fibers of the wool or cotton grass {Erioplwi'imh spp.) and of the 

 arrow grass {Scheuchzeria sp.), roughish from the clustering of 

 cukns, with varying admixtures of the grayish to dark-brown par- 

 tially disintegrated sphagnum mosses and the finely threadlike 

 material from cranberry and similar heaths. 



The coarser fibered Eriophorum component is quite resistant to 

 disintegration and to cutting processes. Wlien relatively pure in com- 

 position Eriophorum peat is deemed of considerable value for textile 

 purposes, the manufacture of cloth, and similar technical uses. 



The type of material in which the plant remains from arrow grass 

 preponderate consists of a reddish finely fibrous network of rootlets 

 inclosing thin scalelike leaves and leaf bases of this plant; the peat 

 material is inclined to be brittle when dry and breaks down into mull 

 or peat dnst. Chemical and other data are given in Tables I and II. 



