126 
alters, while the older shells have it more and more pro- 
minent as they advance in age, besides some contortions, 
such as becoming elliptical, &c. Fig. 1 is a congeries 
from the green sand at Dilton, near Westbury, by favour 
of Lord Compton, who possesses the specimen. Fig. 2 
shows the upper Bat side of the shell. Fig. 3 the lower 
or concave side. Fig. 4 a vermicular appearance which 
some of the brown calcedonic parts put on in spots as if the 
Silex had been dropped in, which spots often accompany 
shells found in the green sand. Fig. 5 is a mass of hardened 
marie with Chlorite sand, the same as Brit. Min. tab. 32 4. 
which seems to include the same shell, as far as I can con- 
jecture, in it the chain-like section appears. It is probable tha& 
this shell belongs to the green sand formation particularly*. 
VERMICULAR! A umbonatau 
TAB. LVIL — Figs. 6 and 7 . 
Sfsc. Char. Discoid, involute, um bona ted above* 
concave beneath, the smallest whorl concealed 
in the umbo. 
The concavity of this shell is but trifling, the last whorlg 
at least in my specimens, is not separated from the others ; 
the central obtuse knob is peculiar. About three-fourths of 
an inch in diameter, and the whorls two or three. 
From the Hamsey marie pit near Lewes, by favour of G. A. 
Mantell, Esq. Fig. 6 the convex or umbonated side ; Fig. 7 
the concave side. It is composed of Carbonate of Lime* 
VERMICULARIA ovata. 
TAB* LVIL— Fig. 8. 
Spec. Char. Discoid, involute, rudely ovate* 
rather the most concave beneath. 
There are about two or three whorls to this wormsheII| 
the longest diameter is about half an inch. 
I gathered it out of Limestone at Shotover hill near Oxford, 
and figure it as adding but little to the plate, and yet useful for 
comparison. I may hereafter meet with it in some variety. 
