191 1.] STEVEXSOX— FORMATION OF COAL BEDS. 63 



ence of plant remains in soil, in every peat bog, justifies us in 

 tracing back in some degree, certain relations of coal formation to 

 similar origin. Accumulation of cannel-like coaly substances can- 

 not be explained otherwise. The tertiary gas coal of Falkenau, 

 pyropissite and Lebertorf all consist of a similar wholly broken up 

 mass of plant parts. External relations had much to do with the 

 conditiens. If inflowing water bring much mineral matter into a 

 bog, the borders are impure while the main portion is pure. So a 

 coal may be impure on the borders and pure in deeper portions of the 

 basin. Even the character of the overlying rock may be important. 



Passing from the composition of the coals, he considers the mode 

 of accumulation; first of all. rejecting absolutely as without founda- 

 tion, the doctrine that coal could have been formed in the open sea 

 and from seaweeds. 



Coal beds consist of alternating, mostly very thin layers, like 

 beds of sedimentary matter ; this, with the fact that they are asso- 

 ciated in series with undoubted sediments, seems to afiford proof 

 for the opinion that coal beds originate as do other sedimentary 

 strata, in contradiction of the so-called peat theory, which accepts 

 the idea of an origin in place after the manner of peat bogs. If 

 one confine his attention solely to this layer-like accumulation and 

 make no further inquiry, the conditions appear so completely ex- 

 plained bv the former doctrine that facts favoring the latter have 

 no value. \'. Gumbel thinks that the presence of upright stems is 

 of comparatively little importance as a proof of autochthonous 

 origin, since their presence is exceptional and it can be explained 

 in. several ways — by drifting, by advance of waters into swamp 

 forests or by plant growths floating on the water. 



A careful examination of the query as to whether or not the 

 lamination of coal can be explained by anything except deposit of 

 suspended matter, leads to surprising results, when extended to the 

 newer coal accumulations. The Quaternary brown coal ofi^ers an 

 instructive illustration of the mode in which the lamination origi- 

 nated. These have absolutely the same structure as that of stone 

 coal beds. It is known positively that they owe their origin to peat- 

 like swamps and that the clayey, sandy partings, which accompany 



63 



