hunter's posthumous paper on fossils. 317 



them [found fossil] ; for hardly any change in the land or sea can take 

 place but what they can follow, — the new rising land, as it were, 

 growing out of the waters, and abandoning the old, which now becomes 

 covered with the waters." — P. xxxviii. 



" But we find wood in greater plenty fossilized, according to the first 

 situation, and which was most probably in the depth of the sea, than 

 the bones of land animals. "We also find wood which has been affected 

 by the sea at two different periods ; first, when in the state of wood, 

 [during which period] it has been eaten by the Pholas [Pholadidce] l , 

 and their canals have been filled with flint, &c. ; and then the wood 

 itself has been changed, I suppose, as above described. "We also find 

 wood eaten everywhere and in all directions by those worms [Teredo 

 antenauta], which we find eating the bottoms of ships at this day, and 

 their canals filled with spar, and the woody texture changed. I have 

 also wood whose mucilaginous parts have been destroyed or decayed, 

 and the interstices, or first canals, which may be considered as sap-vessels, 

 are filled with calcareous earth, making it hard and heavy ; and when 

 steeped in the muriatic acid, the wood comes out to appearance entire, 

 but coidd have been crumbled down to a powder. I have a piece of 

 wood which has lost its mucilaginous part, and its two ends are, as it 

 were, tipped with agate, as if half-changed." 



" We find fossil wood not much different from wainscot ; and what 

 makes me call it fossil wood is, its ends, and some of their interstices, 

 are filled with agate. . . We find agate representing wood in every respect 

 excepting in the species of matter : we find it imbedded in stone, as 

 Portland stone, &c. ; and in such it has commonly undergone a complete 

 change ; and what is very ciuious, it shall be imbedded in a kind of 

 hard freestone, and yet itself shall be agate, therefore has probably 

 undergone a change before it was imbedded : and probably the mode of 

 decomposition and new combination led to this difference between wood 

 and agate ; for as one particle of the vegetable is destroyed or removed, 

 a particle of earth is deposited in its place, something similar to the 

 double elective attraction, something similar to putting a piece of iron 

 into a solution of blue vitriol ; but the particles of earth deposited must 

 be equal in size to the particles of vegetable removed, therefore much 

 more in quantity than what there was of earth in the particles of vege- 

 table ; and one could almost conceive that it was simply an exchange, 

 for the centre of such fossils are commonly much the hardest, while the 

 outer parts appear hardly to be changed. This mode gives the appear- 

 ance of the original structure of wood, giving the strata [of growth], as 



1 [Hunterian Specimens, Nos. 1013, 1014.] 



