392 ON THE FOSSIL BONES OF PACHYDERMATOUS QUADRUPEDS. 



moreover, real fossils, and hear all the marks of a long stay in the in- 

 terior of the earth. Their consistence is altered : their grain is tinged 

 by ferruginous substances : the enamel of the first of these pieces is 

 of a black colour, as is very often the case in fossil teeth ; we may 

 observe upon them some remains of the earthy bed in which they were 

 found; in a word, all that is wanting is some evidence of their origin 

 — a defect which I shall endeavour to supply by some probable con- 

 jectures. 



Peter Camper has also spoken of the fossil teeth of the hippopota- 

 mus, but he seems to have fallen into the same mistake as Daubenton. 

 Here is his article on the subject : it is taken from the Memoirs of the 

 Academy of Petersburgh. (Nova Acta, ii, 1788, page 258). 



"In the British Museum (he writes to M. Pallas), I took a drawing 

 of the molar tooth of a gigantic hippopotamus, which is four times 

 larger than that immense molar tooth, a figure of which I published, 

 and which you described. (Tab. viii, Act. Acad. Petrop. i, Part ii, 

 page 214.") 



Nor did Camper understand by this a tooth of the animal of Ohio, 

 for he speaks at great length of this same animal in the next page ; 

 and besides, we have positive proof that he was well acquainted with 

 it, as he had distinguished it from the hippopotamus in express terms, 

 so early as 1777, in the second part of his Acta, page 219. 



As I have been unable to procure any positive intelligence concern- 

 ing this gigantic tooth, I am obliged to have recourse to conjecture. 

 The teeth of the narrow-toothed mastodon, as I observed in the 

 chapter that treats of them, present, at a certain period of their 

 detrition, trefoil figures resembling those of the hippopotamus ; and as 

 Camper had as yet no idea of the differences which distinguish this 

 animal from that of Ohio, he might have been deceived in the matter 

 of a solitary tooth. However this may be, certain it is that the tooth 

 here spoken of cannot by any possibility be referred to our common 

 hippopotamus, nor to the ordinary fossil hippopotamus, as it exceeds 

 them four times in size. 



Merk would seem to have embraced the erroneous impression of 

 Camper. In the note, at page 21 of his first letter, we find these 

 words : " I have in my possession a molar tooth, found in the environs 

 of Frankfort on the Maine, exactly similar to one of an hippopotamus 

 which is engraved in the first volume of the Epochs of Nature, by 

 M. Buffon, plate 3." Now this plate 3 represents an intermediate 

 tooth of a mastodon of Ohio, the summits of which are somewhat 

 worn. 



M. Deluc, in his fourth letter on Geology, page 414, speaks of the 

 tooth of an hippopotamus found among some volcanic productions in 

 the environs of Frankfort : but Merk tells us in his third letter, page 20 

 (note), that it belonged to a rhinoceros. 



We find more positive testimony upon this subject recorded at a 

 more early period. It is a passage from Antoine de Jussieu, in the 

 Memoirs of the Academy of Sciences for 1724. After describing in 

 detail, and giving a drawing of the head of a real hippopotamus, he 

 goes on to say : " The sight of this head and these feet enabled me to 

 recognise, at first sight, similar petrified bones, found among a number 



