434 THE CANADIAN NATURALIST. [Vol. ix. 



III. ON THE ORIGIN OF ANTHRACITE. 

 (Eead before the National Academy of Sciences, jST. Y., 1880.) 



From comparative studies of carbonaceous minerals as long ago 

 as 1861, the author reached the conclusion that petroleum and 

 anthracite form the extremes of a series, all of which may have 

 been derived from organic matters by natural processes at 

 ordinary temperatures.* 



To this is opposed the ordinary view that anthracite, on the 

 one hand, and petroleum, on the other, result from the action of 

 heat on matters of intermediate composition ; — the one being a 

 distillate, and the other a residuum. Late geological studies, 

 however, show that such an hypothesis is untenable for petroleum, 

 and the author, while cot denying that a local coking of bitumi- 

 nous coals must naturally result from the proximity of igneous 

 rocks, has long taught that it is equally so for our anthracite 

 fields. The prevalent notion has hitherto been that the difierences 

 between these and the bituminous coals farther west are in some 

 way connected with" the mechanical disturbance of the strata in 

 the former region ; but to this is opposed the fact that, while the 

 undisturbed coals of x\rkansas are anthracitic, the highly disturbed 

 coals of north-eastern America, Belgium and other regions are 

 bituminous. 



These considerations I have for many years presented to mj 

 classes in geology, and have maintained that the change which 

 results in the conversion of orsjanic matters into anthracite was 

 effected before the disturbance of the strata ; that the hydrogen 

 was removed, as in ordinary vegetable decay, in the forms of 

 water and marsh-gas; and that differences in aeration, during 

 the processes of change and consolidation of the carboniferous 

 vegetation, are adequate to explain the chemical differences 

 between anthracitic and bituminous coals. Bischof had already 

 enunciated a similar view. 



Prof. J. P. Lesley, to whom I have explained my views, has 

 pointed out that there is an apparent connection in the great 

 Appalachian coal-basin, between the more or less arenaceous and 

 permeable nature of the enclosing sediments and the more or less 

 complete anthracitic character of the coal ; while Principal Dawson 

 informs me that he has observed similar facts in the coal-measures 



• Canadian Naturalist, July, 1861, and Report Smithsonian Institu- 

 tion for 1862 ; also Chem. and Geol. Essays, p. 177. 



