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My observations have been particularly directed to the traces 

 of vegetation in the coal itself, although I have given such atten- 

 tion to those in the shales accompanying it as was necessary for 

 a thorough understanding of the subject. I believe that the 

 investigation of the former branch, hitherto almost untouched, 

 will lead to by far the most interesting results. 



One of the most striking points in this investigation was the 

 appearance, on cleavage, of forms entirely simulating those of 

 well known vegetables of the coal period, yet without a trace of 

 the vegetable, the whole being homogeneous coal. Such are 

 these specimens of Peacock Eye Coal, resembling the roots of 

 Stigmaria, these perfect resemblances of the leaves of Neurop- 

 teris and Cyclopteris, even to the course of the veins. Such, 

 also, are these masses of vessels which have hitherto been 

 thought to be scratches by sliding, but of which I have several 

 specimens on which a small portion of the plant remains, and 

 one on which there is a portion of a cylindrical group of cones 

 of these vessels symmetrically arranged and surrounded by a 

 clearly organic bark or rind. Something of this nature may 

 be seen in a transverse slice of a recent Equisetum. These 

 appearances are not unfrequent, and each in its class is con- 

 stant, the outlines being perfect. Such conditions admit alone 

 of the supposition, that during the consolidation of the coal the 

 mass was in a liquid state, and that each particle of the liquid 

 mass sustained an equal pressure in every part, so that there 

 could be no motion whatever amongst these particles by which 

 the outline of the form could be destroyed, and consequently 

 that all disturbing action took place subsequent to its consolida- 

 tion. The finely polished surfaces are also unquestionably the 

 surfaces of the vegetable. 



Of the same striking nature are the fissures so frequently 

 found on the surfaces of the vegetable imprints, but seldom on 

 the general mass. At first I considered them, as others have 

 done, as mere effects of shrinkage; but after a close examina- 

 tion of some thousand specimens, observing them only on vege- 

 table surfaces, on some containing carbonized vegetable matter 

 differing from all around, on others curved in peculiar forms, so 

 as to shut out the action of any general dynamic law, it occurred 

 to me that the determination of these fissures must have been 



