Mr. Hatchett'j Obfervations on Bituminous Subftances. 



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properties of wood; and that thefe ftrata do not exhibit any of 

 thofe irregularities on their furfaces, which might be expected, 

 on the fuppofition that they were formed by the roots, trunks, 

 and branches of trees long buried in the earth. It is alio dif- 

 ficult to imagine wood to have been tranfported and depofited in 

 this place at feventeen different periods, and yet it muft be allowed 

 that thefe ftrata have been formed by fucceflivc operations. I muft 

 confefs, that after having twice vifited and examined the (put 

 exprelsly for the purpofe, I ftill find myfelf utterly unable to offer 

 any opinion upon thefubject. 



The characters of bitumen are but little apparent in the Bovey 

 coal, and the fuperior ftrata even appear to have loft a portion of 

 their combuftible principle, while the inferior ftrata poftefs it. The 

 lower parts alfo of thefe ftrata are more compacl and more com- 

 buftible than thofe parte which are immediately upon them *. 



Another remarkable fort of foflil wood, which much refembles 

 the Bovey coal, and in like manner is arranged among the bitumi- 

 nous woods, is that found in Iceland, which is called by the inha- 

 bitants Surturbratid. This is rather harder than the Bovey coal, 

 but in every other refpect is the fame. It alfo forms ftrata many- 

 feet in thicknefs ; but it is very extraordinary that thefe ftrata 

 appear to be formed of trunks of trees, which, in their tranfverfc 



* At about ioo yards to the weft of the pita, : is a fog of considerable extent, where 

 peat is cut, and decayed roots and trunks of trees are found, which do not, however, in 

 the leaft approach to the nature of the Bovey coal. Whether this bog has been in any 

 manner connected with the formation of the above-mentioned fubftance, I do not pretend 

 to determine. 



A yellowifh brown com,pac"t. fubftance, which in colour and fraflure refembles ferru- 

 ginous clay, is alfo found occafionally with the Bovey coal ; it is brittle, and is highly 

 inflammable j it melts like a bitumen, and emits a fmoke which in fmell refembles amba . 

 This fubftance is but rarely found. 



T 2 fe^lion. 





