KIMERIDGE CLAY . 
103 
The first bone of the series of 30 is an early dorsal, its 
articular surfaces are 3 inches high and 3 inches wide and slightly 
ovate in outline vertically. Unlike Conybeare’s figure, the peri¬ 
pheral margin is rounded. The articular surface is very nearly 
flat, though a little depressed in the central part, and at the 
centre there is a small conical pit, which a transverse section 
(Case 84.6.8) shows to taper to a line which runs through the 
vertebra. Its thickness at the base is If inch; length of the 
neural canal is lyf inch; the thickness in the central pit is If 
inch ; the height from the middle of the base to the middle of the 
neural canal is 2jf inches. The articular surfaces are minutely 
punctate, and the outer surface concave from front to back. The 
neural canal If in. broad behind; in the middle it is f. The 
extreme width across the centrum at the facets for the neuro- 
pophyses is 3f inches; they are concave, transversely oval, and 
measure If inch wide by If inch long. There are 3 small fora¬ 
mina on each side. An earlier vertebra, seemingly the first dorsal, 
is only If inch in length. The measurements vary a little with 
different specimens, but the proportions are preserved. 
The last of the 30 dorsal centra shows no sign of being near 
the end of the back. It has the same shape of articular surface, 
but it has increased half an inch in width and f ths of an inch in 
height; its front to back thickness is a little less at the neural 
canal than at the base, where it is greatest and measures 2fths 
inches. The intervertebral surface is more decidedly concave 
than in the early dorsal. 
The cervical vertebra, Case 84 . e . 5, measures 3f inches broad, 
2f inches high, and 1J inch thick. The outline is transversely 
ovate, the articular surfaces are flattened with the characteristic 
central pit. The facet for the cervical rib adjoins that for the 
neurapophysis, being nearly 2 inches long and an inch wide. 
In section the vertebrae show no sign of epiphyses. The 
texture is dense under the neural canal and round the outside. 
The cancellous structure is coarse in the centre, but finer near the 
articular surfaces. 
The anterior zygapophyses are just below the upper boundary 
of the neural canal; the posterior zygapophyses are just above it, 
they are oval facets projecting f of an inch, with a little depres¬ 
sion under them in the neural arch. 
