350 



The structure of the fossil tusks of elephants agrees, as might have been 

 expected, exactly with that of the recent. The transverse section shows 

 very small striae, passing in a circular sweep from the centre to the cir- 

 cumference, across each other, and thus forming curvilinear lozenges, 

 which occupy the whole disk. This structure is truly characteristic of 

 the ivory of the elephant, and, as I shall soon show you, of the masto- 

 don, it not being found in the tusks of any other animal. It is much 

 more plainly observable in the decomposing fossil tusk than in the recent 

 one. This peculiarity of structure is shown Plate XX. Fig. 9, the sur- 

 face being slightly magnified. 



The size of the tusks varies according to the species, the sex, and the 

 age ; but no information is yielded respecting the difference of species, by 

 the difference of size in the fossil tusks. It may however be remarked, 

 that they do not appear to exceed in size the tusks, with which the indi- 

 viduals of living species might be furnished, if they were to live to their 

 natural period. 



The curvature of many of the ^fossil tusks agrees with that of the living 

 species, but the curve of the greater number approaches nearly to a semi- 

 circle. Four such have been described; and one of these, by Messer- 

 schmidt and Breyn, in the fortieth volume of the Philosophical Trans- 

 actions. Being apprized, about seven years since, that the remains of 

 some large animal had been found in the brick-fields of Mr. Hobson, at 

 Kingsland, I made the necessary investigations, and learned that a tusk of 

 an elephant had been found between the stratum of gravel and of clay, 

 but in so shattered a state, that only small fragments of it could be re- 

 moved, and that it therefore had been again covered over. One of Mr. 

 Hobson's clerks, a very intelligent gentleman, favoured me with a frag- 

 ment of the tusk, which I now possess, and a fossil oyster-shell, which was 

 found near it. He also obliged me with a sketch, which he had made, 

 chiefly to mark the curvature of the tusk, which appeared to him as very 

 extraordinary. From this sketch, it appears to have formed nearly four 

 fifths of a circle. 



