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there exist the fossil remains of, at least, two species of elephants, 
which were different from those with which we are acquainted. 
The structure of the fossil tusks of elephants agrees, as might be 
expected, exactly with that of the recent. The transverse section 
shows very small strife, passing in a circular sweep from the centre 
to the circumference, 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 mastodon, 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. 1, the surface 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 individuals 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 nearlv 
to a semicircle. Four such have been described ; and one of these, 
by Messerschmidt and Brevn, in the fortieth volume of the Philoso- 
phical Transactions. 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 removed, and that it therefore had 
been again covered over. One of Mr. Hobson’s clerks, a very intel- 
ligent gentleman, favoured me with a fragment of the tusk, which I 
now possess, and a fossil oyster-shell, which was found near it. He 
