2 
marble, and I think superior to the Broad Marston Am« 
monites mentioned by Dr. Maton in his Tour, II. p. 21. 
(Ammonites planicosta figured in my plate 73.) Fig. 2. 
shows a good specimen; imagination must supply the 
figure with lustre, which when the surface is made pellucid 
with wet is most perfect, yet if gummed is nearly oblit- 
erated. Fig. 1 is a small specimen which is less angular 
but contains the centre (which is commonly lost in larger 
or older specimens) whole: at the top, near the figure, is 
a small vestige of the siphuncle, nearly black, which in 
some specimens is preserved very distinctly, while it ap- 
pears, from others which are far more perfect, impossible 
for a siphuncle to exist: it is in the front as is most com- 
mon. Figure 3 is a pyritaceous cast, and exhibits the 
foliated sutures which are more or less conspicuous and a 
little peculiar in the continuous structure below the higher 
risings of the radii, which are rather blunter than in the 
upper figure. A species nearly resembling this is, I be- 
lieve, found at Westbrook in Wilts. 
