314 PALiEONTOLOGT. 



but which I believe are seldom called ' fossils.' But we have many 

 extraneous fossils imitating all the appearance of wood, many of 

 which had wood for their base ; we have also the impressions of 

 leaves, <fcc. 



" But pure animal substance without any mixture of earth, stands 

 still a less chance of becoming the basis of a fossil ; for they are more 

 dissolvable in themselves, or perishable, than most vegetables ; even less 

 chance of having a moidd formed upon them ; therefore we have fewer 

 of them. However, some animal substances are solid enough to pre- 

 serve them a sufficient time to have a mould formed upon them, viz. 

 the scales of the turtle, fish, and some insects, (fee. : even horns might be 

 preserved a sufficient time. However, of these two last there are very 

 few in number that can have the opportunity of having a mould made 

 upon them ; but as we have no casts of the beaks of the cuttle-fish in 

 a fossil state, we may suppose that even this substance is not sufficiently 

 preservable 1 . 



" The difference of the impressions of fish in marl schistus, and in the 

 bituminous schistus, appears remarkable. In the marl schisti which 

 contain impressions, such as those of Verona 2 and Pappenheim, it is the 

 skeleton of the fish which has made the principal impression, whilst 

 the skin appears like a film (which certainly helps to make manifest the 

 figure best), through which the impression of the bones are distinctly 

 seen, as if the soft parts of the animal had decayed before the mould 

 was made. On the contrary, in the bituminous schist, such as those of 

 Eisleben 3 , the figure of the fish appears complete, as if the impression 

 was made before any part of the animal had suffered any alteration by 

 putrefaction; it is probable that this difference has been occasioned 

 by the property of bitumen in retarding or preventing putrefaction." — 

 P. xxvi. 



The principal, perhaps sole, cause of the difference here noted by 

 Hunter between the Ichthyolites of the tertiary schists of Yerona and 



1 [Hunter, when he wrote this passage, had either not received, or not given his 

 usual attention to, the beautiful fossil from the oolitic slate of Solenhofen, No. 2, 

 ' Catalogue of Invertebrate Fossils,' in which, after determining its nature under the 

 name of Leptotcuthis gracilis, I described " the mandibles as moderately long, slender, 

 slightly arched, trenchant, pointed, and wholly horny, as in other Dibranchiate 

 cephalopoda."— P. 3. 4to, 1856.] 



2 [Catalogue of Fossil Reptiles and Fishes, No. 641, Smerdis micracanthus, 

 " from Mount Yisiena Nova, near Yerona."] 



3 [lb. No. 613, "Impression of a Fish: the head quite crushed, the tail also 

 crushed: many of the scales are bronzed: from Eisleben, near Mansfeldt, Upper 

 Saxony." Orig. Himterian Catalogue. In the ' Catalogue of Fossil Reptiles and 

 Fishes,' 4to, 1854, p. 153.] 



