452 ORIGIN OF THE AI'rALACUIAN COAL STRATA, 



and uniform distribution of the layers in the coal, there is another, 

 drawn from the striking deficiency of earthy sedimentary parti- 

 cles. In many of the purest layers, the total proportion by weight 

 of foreign mineral substance, in the coal, is less than two per 

 cent., sometimes barely one per cent., while the ratio by bulk is 

 consequently less than one half of this. So extremely insignificant 

 a quantity is what we should expect, on the hypothesis of a tran- 

 (|uil accumulation in wide sea-meadows, extending far out from 

 the edge ol' the ancient shore, where no turbid currents could get 

 access. It is as inconsistent, on the other hand, with the notion 

 of a drifting of the vegetable matter itself, which, according to 

 any conceivable mode of transportation, would be accompanied 

 by a large amount of earthy matter, such as abounds in all deltal 

 deposits, and even mingles with the wood in the raft of the Atch- 

 afalaya. That so nearly the whole of the suspended mineral 

 matter, even to the fine particles of impalpable clay, should have 

 subsided, in almost every instance, before the first portions of the 

 floating vegetation sank, contradicts all observation respecting 

 similar actions now occurring. The introduction of any argilla- 

 ceous matter into the transparent waters of the great peat morasses, 

 must have happened in the manner of an exceedingly quiet and 

 diffused silting in, or more properly a slow intermingling, of very 

 slightly turbid water with that of the limpid sea. The above ar- 

 guments from the uniformity in the disti'ibution of the vegetable 

 matter of the coal-seams, and from the absence of earthy matters 

 in the coal, have been already employed by Mr. Beaumont as 

 objections to the drift theory, in a communication read to the 

 Geological Society of London, February 26th, 1840.* 



Of TiiK Character of the Strata in immediate contact 



WITH the CoaL-SeAMS. 



Turning from the structure of the coal itself, to the character of 

 the strata, usually in immediate contact with it, we discover cer- 

 tain prevailing relations, from which, by a careful study, much 



* Beaumont, Proceedings Geol. See. No. 69. ' 



