424 REPORT OF NATIONAL MUSEUM, 1899. 



converted into anthracite through the intrusion of a mass of an ande- 

 sitic trachyte/ 



Prof. J. J. Stevenson has, however, argued' that the difference 

 between anthracite and the ])ituminous coals is due, not to metamor- 

 phism through heat and pressure after being buried, but rather to the 

 former having been longer exposed to the percolating action of water, 

 whereby the volatile constituents were removed, prior to its final 

 burial, and the consolidation of the inclosing rocks. 



The subject is, however, altogether too large to be satisfactorily dis- 

 cussed here, and the reader is referred to the special works on the 

 subject noted in the bibliography. 



Peat represents the plant matter in its least changed condition. It 

 results from the gradual accuiuulation in bogs and marshes of growths 

 consisting mainl}^ of sphagnous mosses, a low order of plants having 

 the faculty of continuing in growth upward as they die off below. In 

 this way the deposits often assume a very considerable thickness. 

 When sufficently thick the weight of the overlying matter may have 

 converted the lower portions into a dense brownish-black mass some- 

 what 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 — about one-seventh of the entire country 

 being covered by them — and average in some cases 25 feet in thick- 

 ness. (Specimen No. 53242, U.S.N.M., from County Kerry.) They 

 are also abundant on the continent of Europe and various parts of 

 North America. In Europe, and especially in Ireland, the material 

 is extensively utilized for fuel, and there would seem no good reason 

 for not so utilizing it in America. As prepared for use the material 

 is simply dug f i-om the bogs and stacked up until sufficiently dr}' for 

 burning, or pressed into bricks of suitable size and shape for conven- 

 ient handling. Many processes have been invented for reducing the 

 material to a pulp and subsequently condensing by pressure, but all 

 involve too great an outlay to be profitable.^ 



In America the chief use of the material is as a fertilizer, a material 

 for ""mulching.'J An impure variety containing a considerable quan- 



^ Bulletin of the Geological Society of America, VII, 1895-96, p. 525. 



2 Idem, V, 1894, p. 39. 



^ A new method of making charcoal from peat has heen patented in England hy 

 Mr. Bhmdell and is to be tried in Italy, where there are large deposits of peat which 

 can, it is claimed, be handled very cheaply. In this process the peat is first reduced 

 to a fine paste and leaves the machine in a continuous thick tube 3 to 5 inches in 

 diameter, and is then cut off in sticks and dried for three days on wooden supports 

 and for a longer period in the air on wire netting. After twenty-five days the sticks 

 become dry and hard and may be burned as fuel; but it is more profitable to convert 

 these sticks into charcoal. This is accomplished in six hours in a retort, and 3 tons 

 of peat make 1 ton of charcoal. — Engineering and Mining Journal, LXV, February 26, 

 1898, p. 248. 



