R. Lydekker—A Wealden Celuroid Dinosaur. 119 
coincides with a suggestion of Lyell’s, that “they have been the 
result of intense pressure, so moderated as to be just sufficient to 
overcome the resistance opposed to it; and that this motion has been 
as insensible as the unfolding of the petals of a flower.” ? 
Professor A. Favre of Geneva gives in “ La Nature” illustrations 
of experiments? in which layers of plastic clay were laid upon a 
sheet of caoutchouc, stretched one-third more than its length; on 
being allowed to resume its normal dimensions, the bands of clay 
were diminished to that extent, and became greatly contorted. The 
experiments were conceived for the purpose of illustrating the 
method of formation of the great inequalities on the earth’s surface, 
such as mountains, etc., by means of lateral thrust or crushing, 
which are considered by him to be due to the cooling of the earth. 
They do not appear at all applicable in explaining the cause of 
eminences and depressions in the contour of the land; they more 
nearly represent those foldings and contortions of strata which have 
been universally attributed, since the time of Sir James Hall, to 
lateral pressure ; but it is too much to conceive that from any con- 
traction, whether by loss of heat or otherwise, extensive areas have 
been compressed into a third less than their original dimensions ; as 
this is a condition of by no means infrequent occurrence in geological 
formations, the cause of the compression and consequent foldings of 
strata must be searched for in other directions. 
(To be continued.) 
VIII.—On a Ca@iuror Dinosaur FrRoM THE WEALDEN. 
By R. Lyprexxer, B.A., F.G.S., ete. 
ie going through the remains of Chelonia preserved in the British 
Museum I came across two vertebrae from the Wealden of the 
Isle of Wight, which had been inadvertently included in that 
series. These specimens (B.M. No. R. 901) formed part of the 
collection of the late Rev. Mr. Fox, and clearly indicate a small 
Dinosaur allied to the genus Celurus. 
Both specimens belong to the cervical region, and are precisely 
similar; but whereas one is almost entire, the other has lost nearly 
the whole of the neural arch. The former specimen is_repre- 
sented of two-thirds the natural size in the accompanying woodcut ; 
from which it will be seen that it is practically entire, with the 
exception of the loss of the greater part of the ribs (see p. 120). 
The chief characters of this specimen may be summarized as 
follows. The vertebra is considerably elongated, with a markedly 
opisthoccelous centrum, of which the terminal faces are oblique. 
The arch is comparatively low, with only a slight ridge to represent 
the neural spine. The ribs were anchylosed to the arch and 
centrum, and (from the contour of the basal portion) were evidently 
much bowed outwards. The sides of the centrum exhibit a pneu- 
1 Quart. Journ. Geol. Soc. vol. vi. p. lxiii. 
2 They are copied in ‘‘ Nature,’’ vol. xix. December 5, 1878, p. 103. The Rev. 
Osmond Fisher has reproduced one in “ Physics of the Earth’s Crust,” p. 128, but 
does not coincide with the deduction Prof. Favre draws from the experiments. 
