1855,] HARKNESS ANTHRACITE-SCHISTS. 471 



deposit has derived its carbonaceous matter from the existence of 

 sea-weeds during the earher portion of the Lower Silurian epoch. 



In order to obtain more intimate knowledge with regard to the 

 origin of the anthracite, I submitted portions of it to a minute mi- 

 croscopical examination, both in the form of powder and likewise in 

 the state of ash. In no case, however, could I obtain anything 

 which indicated vegetable structure, the ash presenting itself in the 

 form of minute grains of quartz, having upon them the transverse 

 striation prevaihng in this mineral. Through the kindness of my 

 friend and colleague Dr. Blyth, T am enabled also to give the ana- 

 lysis of the anthracitic schists, which is as follows : — 



Water 1-05 



Carbon 5*05 



Ashes 93-90 



100-00 

 The ashes consist of, — 



Silica 96-83 



Iron 2-27 



Alumina 0*90 



Lime a trace 



100-00 



From this analysis of the ashes of the anthracite-schists, they ap- 

 pear in their mineral composition to approach exceedingly near to 

 the nature of pure quartz ; and it would seem that these schists were 

 originally beds of fine sand, or, in other words, sand-banks, impreg- 

 nated with organic substances. The question as to the source from 

 whence the carbon has been derived, is in no way answered by the 

 microscopical examination, or by the analysis, except that this latter 

 points to an affinity to some of the coal-measure shales rich in car- 

 bon, and renders the circumstance probable, that, like these coal- 

 shales, the anthracite was obtained from altered vegetable matter. 

 The occurrence of such animal remains as are seen in these schists in 

 the form of iron pyrites rather than as carbonaceous markings, would 

 also justify the inference that the carbon of these shales had a dif- 

 ferent origin from that which had entered into the composition of 

 the Graptolites when these were living animals, and would, to 

 some extent, lead to the conclusion that vegetable remains furnished 

 this substance, — an inference which is further supported by the 

 appearance of a genus of Crustaceans, the Dithyrocaris^ which had 

 its habitat among the vegetable mud of the succeeding carboniferous 

 formation. 



When we consider the large portion of earthy matter in the an- 

 thracitic shales, we must regard them as having an origin in some 

 respect allied to that of coals which contain a large amount of earthy 

 substances, although the latter derive their organic matter from a 

 different class of vegetables. And if we bear in mind the low organ- 

 ization of Fucoids, which consist of a simple mass of parenchymatous 

 tissue of a very succulent character, we can easily conceive how 



