594 PROF. H. G. SEELEY ON THE DINOSAURIA OF 
Parr I. 
Note on the axis of a Dinosaur from the Cambridge Greensand, 
preserved in the Woodwardian Museum of the University of 
Cambridge (fig. 1). 
The more important bones which are absolutely distinctive of the 
Dinosaurian skeleton, such as the pelvis, astragalus, &c., have not 
been met with from the Cambridge Greensand ; and though there 
have been obtained from that formation a large number of isolated 
and associated bones, which belong to several extinct genera, each 
haying more or less in common with the described types of Dino- 
saurs beyond all question referable to the group, there is probably 
no bone more characteristic of the order than a badly preserved 
example of the second cervical vertebra. This solitary specimen is 
the result of more than a quarter of a century of zealous research, 
Fig. 1.—Awis of Acanthopholis ?, nearly nat. size. 
o. Odontoid process. 
p. Pedicle of centrum supporting the neural arch, below which are the articu- 
lations for the rib. 
pt. Posterior articular surface of centrum. 
carried on by many collectors under opportunities which have never 
been surpassed; and therefore, though it only confirms, under certain 
generic differences, the characters of the axis from the Wealden de- 
scribed by me some time ago*, itseems worthy of a brief memorandum 
as showing that the Dinosauria retained this typical characteristic 
to so late a geological period as the Cambridge Upper Greensand. 
The state of preservation of the fossil would suggest to me that 
it was probably found in the neighbourhood of Haslingfield. The 
neural arch is not preserved, and but little remains of the external 
hard film of bone; but although this is lost, and the cancellous tissue 
is almost everywhere exposed, the close resemblance of its form to 
the centrum of the Wealden axis strongly suggests that this con- 
dition is more likely to have resulted from prolonged exposure to 
the air, or from maceration, coupled perhaps with the action of sol- 
vents in the water, than to have been produced by attrition, though 
the marks of wearing are also observable. Therefore the specimen 
* Quart. Journ. Geol, Soc. yol. xxxi. p. 461. 
