4S Observations on the. Change of 



imdQubtcdly a remarkable fact ; but if it were unsupported 

 by any ulbcr, the onlv inference would be, that the scliistus 

 vvcLs nu)st probably of very recent formation, and had been 

 produced under peculiar circunib^tances. 



I was desirous, therefore, to discover some similar cases 

 which might serve as additional corroborative proofs of the 

 gradual alterations by which vegetable bodies become 

 chunued, so as at length to be regarded as forniinci; part of 

 the mineral kinsjdom; and from the reasons which have 

 been stated in the eommenceinent of this paper, as well as 

 fiom a certain similarit}' in the external character? of the 

 substance coniposiuiT the leaves abovementioned with those 

 of the Bovey coal, I was induced to make this last also a 

 suijiect of chemical inquiry. 



hi the Philosophical Transactions for the year 176O*, 

 some remarks oft the Bovcy coal, and an account of the 

 strata, are stated, in a letter fron) the Kcv. Dr. Milles to 

 the Earl of Macjlesfield. The object, indeed, of the author 

 was to establish that this and similar substances are not of 

 vciietable but of mineral origin ; and, to prove this, be 

 adduces a great number of cases, most of which, however, 

 in the present state of natural history and of chemistrv, inus* 

 be regarded as proving the contrary ; whilst others, men- 

 tioned by him, such as the Kinnneiidge or Kiniendgeeoal, 

 are nothino" more than bituuunous slates, and of course arc 

 of a very ditterent nature. 



Dr. Milles's account of the varieties of the Bovey coal, 

 and of the state of the pits at that time, appears to be very 

 accurate; and for the present state, or at least such as it 

 was in ITtiG, I shall beg leave to refer to a paper of mine, 

 published in the fourth volume of the Transactions of the 

 Linnean Society f ; for, as this is more immediately a che- 

 mical investigation, I wish to avoid, as nnich as possible, 

 entering into any minute detail of geological circumstances. 



It may however be proper to observe, that tlie Bovey coal 

 is found in strata, corresponding in almost cvi ry particular 

 with those of the surturbrand in Iceland described by ven 

 Troil X and bv Professor Bergmanu§. The different 

 strata of both these substances are likewise similar, beina; 

 composed of wood or trunks of trees, whieh have com- 

 pletely lost their cylindrical form, and arc perfectly flattened, 



■•" Vol. li. p. ;'^i}.. 



■\ Obscrv.Tiicni on bituminous Siilittances, p. 13S. — See also Parkin- 

 son's Oii^anic Remains of a former V\'tji'M, vol. i. p. 126. 

 + Von Troll's Letters, p, 4.2. 

 § O/.v . .vAi Bcr^nianni, tuai. iii. D^ PfWii.//.' ./'i.A<i,';//.!, p. 239. 



2 as 



