found at Richmond, Virginia. 231 
This tooth (fig. 4,)is 12 o. in length, having a small portion 
broken from the end of its root. ‘The crown is conical, com- 
pressed on its inner pore: vil slightly trenchant edges, the pos- 
terior of which is provided with a slightly projecting tubercle. 
The enamel over its hice surface is roughened by small irregu- 
lar ridges, the general direction of which is from the base towards 
the apex of the crown, those at the apex being the most minute. 
This tooth must have been placed at the anterior part of the 
~ all those of the posterior lateral portions being deeply in- 
ented. 
Dr. Burton has also found a petrous bone with its convoluted 
appendage, which has all the Cetacean oo and which 
rof. Agassiz likewise refers to the genus Phoco 
elphin nus.—F rom the same locality and in pes immediate 
neighborhood of the spot in which the vertebree and other bones 
of the seal were found, Dr. Burton obtained four vertebra all 
ee apparently to one individual and nearly of the size of =~ 
those of the common porpoise, (D. delphis. ‘, 
3 fragment of a lower jaw represented in figures 5 and 6, eT 
the indications of the teeth are followed, is Cetacean, ‘though t 
jaw itself issomewhat unusual. ‘The crowns proiee ‘but Bois 
above their alveoli, and are small when compared with the roots — 
which are long, bulging near the middle and deeply imbedded in 
their sockets. The t to which they peuetrate into the jaw 
is made obvious by ‘he fractures, which intersect way ek, 
near their termination. A reptilian age in the j 
* 
recognized in the depressions or grooves which exist on it sides i in- ‘ 
the intervals between the teeth, as if for the cree 2 of ae by 
teeth of the upper maxillary bone, a condition which , *s 
Gibbes has shown to exist in the Basilosaurus. Each fot is sur- ~ 
rounded by a distinct circular ridge. The teet lid the 4 4 
pulp cavity Phsing wholly filled up. By refere neeigy re. ; 
be seen that the two halves of the lower j jaw arg iitited through * “4 
the whole extent of this fragment (t poympiyse by a flat s sur + 
face as is the case in the sperm whale: am 
Crocodiles. It differs however from 1e lattel 
an enlargement of the jaw at its extremity, 
ing toa a poi nt as in Cetaceans,) as well as in 
teeth of larger dimensions:which in Gayidls co corr 
Were it not for the prolonged: sym phys 
garded as belonging to the genus ns PI 
nT resembles-that,of some s 
Lot the oat he 1 fi : 
