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which had been immersed in water, and had suffered decay. But 
he soon, however, changed his opinion, when he considered, how 
prodigious the quantity was of which it consisted ; which, he thought, 
must have been vastly beyond what could have been furnished by 
any forest. Again, had it been of diluvian origin, he expected, that 
he should have found the vegetable ruins scattered, in detached and 
irregular masses ; but here the vein of bituminous matter had, every 
where, an uniform appearance, and constantly preserved the same 
rectilinear course, undisturbed by the inequality of the mountain. 
Besides, in this wood, he could discover no transverse fibres ; nor 
could he find with it either bark, branches, or leaves. From these 
circumstances, he was induced to relinquish the opinion, that it had 
ever belonged to the vegetable kingdom; and concluded it to be 
entirely of mineral origin. Bitumen possessing, in his opinion, a 
peculiar innate, and to us a hidden power of coagulating and assum- 
ing the form of wood ; this being a work not of the subterranean 
archceus, but the result of a specific power, inherent in the bitumen. 
Above and beneath this stratum of bituminous matter, is a bed of 
very fine potter’s clay, about six feet thick, which keeps the same 
horizontal level, and passes along with the fossil wood, directly in a 
straight line, through every recess of the mountain, neither rising or 
declining with its slope*. 
Francisco Stelluti, in 1637, described some strata of fossil wood, 
found near Todi and Aqua Sparta, in Umbria ; the description of 
which exactly accords with the kind which we are at present ex- 
amining, in its consisting of large oval and compressed pieces, lying 
horizontally, resembling the trunks of trees, but larger, some being 
above three feet broad ; in having neither roots, branches, nor fibres, 
but something like bark; and something resembling the heart of 
* Bitumen et lignum fossile bituminosum descriptum a D. Matthia Zaccharia Pillingen, 
medica Altenburgensi. Altenbergi, anno 1674. 
