147 
AMMONITES vertebralis* 
TAB. CLXV. 
Spec. Char Discoid, radiated,, and carinated ; 
inner volutions partly concealed ; radii promi- 
nent, numerous, tuberculatedin the middle, then 
furcate, with a tubercle upon each branch ; 
carina serrato-tuberculate ; aperture orbicular. 
A very handsome shell whose radii are a little undu- 
lated, and together with the tubercles upon them, are 
sharpish and compressed ; they are very regularly fur- 
cate, and each branch has a tubercle about its middle, 
then passes on in an elegant curve to the carina, where 
it forms another somewhat reflected tubercle-— the two 
branches again unite on the other side. The thickness 
is about equal to one-third of the diameter. 
The Rev. W. Buckland has enabled me to exhibit this 
with his usual fondness for science ; he informs me that 
it is found at Dry Sandford and Marcham, two adjoining 
villages on the N. W. of Abingdon, Berkshire, where 
it lies in silicious sandy beds, that contain subordinate 
Strata of a gritty Limestone, composed of small Quartz 
pebbles, sand, and shelly fragments, united by a calca- 
reous cement. 
I have not seen the outside of the shell, but from the 
space between the whorls in the cast, I suppose it must 
have been thick. It is named vertebralis from the re- 
semblance of the carina to the vertebral processes in some 
quadrupeds. 
