PEAT AND LIGNITE 



129 



of North Carolina marls, consisting largely of comminuted 

 shells and sometimes coprolite nodules, will serve to show the 

 widely varying character of the materials grouped under this 

 name.^ 



(3) The Carbonaceous Group: Peat, Lignite, and Coal.— 

 Here are included a variety of more or less oxygenated hydro- 

 carbons varying widely in physical and chemical properties, but 

 alike in originating from decomposing plant growth protected 

 from the oxidizing influences of the air. Plants, when decom- 

 posing upon the surface of the ground, give off their carbon to 

 the atmosphere in the shape of carbonic acid gas (CO^), leaving 

 only the strictly inorganic or mineral matter behind. When, 

 however, protected from this oxidizing influence by water, or 

 other plant growth, decomposition is greatly retarded, varying 

 portions of the carbonaceous and volatile matters are retained, 

 and the material becomes slowly converted into coal. Accord- 

 ing to the amount of change that has taken place in the original 

 plant material, the amount of volatile matter still retained by it, 

 its hardness and burning qualities, several varieties are recog- 

 nized, which, however, pass into each other by insensible grada- 

 tions. 



Peat results from the gradual accumulation in bogs and 

 marshes of growths consisting mainly of sphagnous mosses, a low 

 order of plants having the faculty of continuing in growth 

 upwards as they die off below. In this way deposits often 

 assume a very considerable thickness. Where sufficiently thick, 

 the lower portions have sometimes been converted into a dense 

 brownish black mass somewhat resembling true coal. The 

 deposits of peat are all comparatively recent and occur only 

 in humid climates. They are developed to an enormous 

 extent in Ireland, and are also abundant in Europe and various 



Constituents 



I 



11 



m 



Carbon 



Volatile matter 



Ash 



61.04 % 

 37.53 

 1.83 



23.86 fo 



56.13 



19.77 



21.00 fo 

 72.00 

 7.00 







Totals 



100.40 % 



99.76 fo 



100.00 fo 



^Geology of North Carolina, Yol. I, 1875, p. 195. 

 10 



