Situm'inous Woody Sur-iurirafid, bfc. 207 



Another remarkable fort of foffil wood, which much refembles the Bovey coal, and in like 

 manner is arranged among the bituminous woods, is that found in Iceland, which is called 

 by the inhabitants Surturbrand. This is rather harder than the Bovey coal, but in every 

 other refpeft is the fame. It alfo forms ftrata many feet in thicknefs ; but it is very extra- 

 ordinary that thefe ftrata appear to be formed of trunks of trees, which, in their tranfverfe 

 fe£lion, exhibit the concentric circles of their annualgrowth, with this difference,' that the 

 trunks have been fo comprefTed as to be nearly flat, fo that the circles appear like parallel 

 lines conneited at their extremities by a fliort curve. 



I did not obferve fuch an appearance at Bovey ; but this would depend upon the pofitioh 

 of the trunks of the trees, in refpeft to the fedlion of the ftrata. 



Chaptal*, Troilf, Bergman J, and many others, have been of opinion that the furturbrand 

 is wood which has been charred by the heat of the lava. But I cannot difcem why it Ihould 

 be fuppofed that it has been a£led upon by fire, any more than that the Bovey coal has been 

 fubjeded to the efFe(fts of the fame agent. The qualities of the two fubftances are the famej , 

 and as (from Archbifhop ■ Troll's and ProfelTor Bergman's account) the furturbrand is 

 flratified, I think we may venture to pronounce that the circumftances under which they 

 are found, are alfo fimilar§. The whole, therefore, of the opinion in falvour of fire, appears 



«oal. Whether this hog has been in any manner connefted with the formation of the. above-mentioned fub- 

 ftance, I do not pretend to determine. 



A yellowifh brown compaft fubftmce, which in colourand fracture refembles ferruginous clay, is alfo found 

 occafionally with the Bovey coal : it' is brittle, and is highly inflammable; it melts like a bitumen, and emits a 

 fmoke which in fmell refembles amber. This fubftance is but rarely found.' 



• Element! of Chcmiftry, vol. iii. p. 197. 



f Von Troll's Letters, p. 43. 



J Quid de ligno folhli Iflandix fentiendum fit, gnaro in loco natali contemphtori decidendum relinquimus. 

 Interea, utcum Vulcani operationibus nexum credamus, plures fuadent rationes, quamvis hue ufque modum 

 ignoremus, quo fitum texturamque adquifiverunthaec ftrata. Scilicet truncis arborum perquam craffis coiiftant, 

 qualis in Iflandia nul'ibi repcriuntur, et ne quidem hoc tempore crefcere poile videntur. Hi fitu horizontal! 

 in ftratis multorum pedum craffitiei congefti funt ct petrolco plus minus penetrati, non jam moUi, fed optime 

 indurato, a quo tam nigrorem, quam flammae fub deflagratione qualitatem mutuantur. Sed quod in primis 

 attentionem merctur, ell truncorum in lamellas planas comprcffio. 



Ponamus truncum arboris cujufdam tranfverfim feftum, hinc, uti notum efl:, figura oritur in orbem redicns 

 circiter circularis, qurt omnia monftrat anuotina incrementa, extimo ptopemodum parallcla. . Fingamus jam .v 

 talem fe&ionem in tenuem laminam comprtffam, et veram habebvmus ligni foflilis, de quo hcic agitur, ideam'; 

 nam in magnis hujus materis fruftis, tranfvcrfim feftis, quemlibet annotinorum orbium vifu pcrfequj licet, ita 

 plerumqiie coaftum, ut duas lineas fere parallelas exhibeat, quarumextrema brevi flexura funt adunata. — Qua 

 autem immanis requiritur vis, ut truncus cylindricus ita complanetur ? Nonne antea particulai'um nexus 

 putredinis qucdam gvadu fuerit relaxatus ? Certe, nifi compages quodammodo mutatur, quodlibet pondus in- 

 cumbens huieeffeflui erit inipar. Ca;terum idemobfervatur phsenomenon in omni fchiftoargUlaceo>'-. 



Onhoceratitse, qusin ftrato calcareo conicam figurara perfeQe fervam, jn fchifto,planum fere triahgulare 

 comprefliorie efliciunt. Idem valet de pifcibus, , conchis, infeftifque petrifaftis. Caufa adbuc latet, fed in 

 Utroque cafu fine dubio eadem eft, et digna quje exploretur. Obfervatu quoque dignum eft, quod idem 

 reperiatur t-ffeftus, quamvis ftratum calcareum fub fchifto collocatum fit et majori ideo ponderfi comprimentc 

 onuftum. -Bergman de Produftis Vulcaniis Opufcula, torn, iii^ p. 239. ,. 



§ " It is found (the furturbrand) in many parts of Iceland, generally in the mountains, in horizontal beds; 

 fometimes more than one is to be met with, as in the mountain of Lack in Bardeftrand, where four flrata of • 



iurturbrand are found alternately with different kinds of Jdone.,''— Troil's.Lctters, p. 44, ,, 



