140 Hugh Taylor, Esq., on the Chemical Constitution 



On the Chemical Constitution of the Bocks of the Coal For- 

 mation. By Hugh Taylor, Esq.* Communicated by 

 the Author. 



Up to a very recent period the attention of geologists has scarcely 

 been directed to the facts which chemistry is capable of supplying 

 in support of the doctrines of their science, although it admits 

 of no doubt that the analysis of rocks and comparison of their 

 chemical characters may in many instances materially contribute to 

 the solution of its problems, or to the determination of disputed 

 points. Of late, however, the chemical investigation of the volcanic 

 rocks of Iceland and of some other districts has led to interesting re- 

 sults, and though the stratified rocks in some respects afford a less 

 promising field of inquiry, much valuable information may be 

 derived from a knowledge of their chemical composition.'!' In regard 

 to this class of rocks, we are still almost entirely destitute of chemical 

 information ; and, under these circumstances, I venture to hope that 

 the following analyses of the rocks of the coal formation may not be 

 without value, in so far as, to the best of my knowledge, none of 

 them — with the exception of coal itself — have yet been analysed. 

 The analyses were made in the laboratory of Dr Anderson of Edin- 

 burgh, to whose kind assistance and encouragement I have been 

 much indebted during their prosecution. 



The rocks analysed were taken principally from Buddie's Hartley 

 Colliery in the Newcastle coal field, and, though few in number, are 

 calculated to throw more light on the general constitution of such 

 rocks than might be at first sight expected, each specimen being 

 selected as the type of a family, the members of which differ little 

 in their physical or chemical properties ; so much so, indeed, that no 

 difficulty exists in referring any individual stratum to the family to 

 which it belongs. 



On examining the section of the coal field, a certain definite ar- 

 rangement of the beds is apparent, and a tendency to the repetition 

 of small groups of strata — each group consisting of the same, or 

 nearly the same, series of rocks. The succession of the members of 

 those groups is, of course, liable to a certain amount of variation, in- 

 dividual beds sometimes disappearing or " cropping out" — and so 

 destroying the uniformity of the series ; but it maybe observed gene- 

 rally that each seam of coal is the centre of a group, and is enclosed 

 above and below by a succession of strata more or less impregnated 

 by bituminous or coaly matter, those in immediate contact with the 



* Read to the British Association at Edinburgh, August 1850. 



t We recommend to the particular attention of students of the chemistry of 

 rocks the many valuable memoirs of Mr M. A. Delesse in the Annalos des 

 Mines, &c. ; and also the important Jjehrbuch der Chemischen und Physikalis- 

 chen Geologic of the celebrated Dr Gustav Bischof.— .feWf. of Edin. Phil. Jour. 



