ON SOME AMPHIBIAN AND REPTILIAN REMAINS 121 
which is bounded by the contour of the skull has separated from 
the rest, leaving in its concave counterpart the outer bony crust of 
the mandible and a portion of the maxillary bones. I had hoped 
that the fossil might be relieved in such a manner as to show, not 
only the structure of the under part of the skull, but the character 
of the occipital articulation; but the matrix is so exceedingly hard, 
and the bony matter so soft and fragile, that even my experienced 
and skilful ally, Mr. Dew, was afraid of carrying on his excavations 
sufficiently far to attain these objects. 
Sufficient has been done, however, to reveal the indistinct re- 
mainder of the anterior part of the vertebral column, and to prove, 
by its means, at what point the occipital region of the skull was 
situated. From this it appears that the postero-lateral angles of the 
cranium were produced for $ths of an inch behind the general plane 
of the occipital surface. 
The most striking features in the skull are the large oval orbits, 
which occupy, as nearly as may be, the middle third of the space 
between the occiput and the end of the snout. The long axes 
converge a little anteriorly ; and the interorbital space (which is not 
equal to more than one-fourth of the diameter of the skull), opposite 
the middle of the orbits, is far narrower than the transverse diameter 
of the orbit. 
The nostrils are rounded apertures, distant less than twice their 
own antero-posterior diameter from the anterior edge of the orbit ; 
they are placed very near the anterior edges of the snout, and are 
separated transversely by an interval equal to the interorbital space. 
Their long axes are, like those of the orbits, directed obliquely in- 
wards and forwards. Both orbits and nostrils look upwards and 
outwards, the former direction predominating. The vertical diameter 
of the skull (including the mandible) is greatest posteriorly; but 
even here the thickness does not attain one-fourth of the length ; 
and the vertical diameter gradually diminishes anteriorly, until, at 
the end of the snout, the thickness does not exceed an eighteenth of 
the length. 
The left premaxillary bone appears to be nearly entire. It is very 
short, its horizontal portion extending backwards only to the middle 
of the external nostril, the anterior part of whose inferior boundary 
jt forms. At its inner end, the premaxilla gives off a broad but 
short, ascending, recurved process, which forms the anterior and 
internal boundary of the external nostril and ends superiorly in a 
point. Whether it is broken off here, or not, I cannot say. 
The maxilla meets the posterior end of the premaxilla, and then 
