Ammonites giganteus, found in the Portland stone at
Tisbury in Wiltshire. This beautiful fossil is in the collection
of Miss Benett. The chambers are all void, and
the transverse Plates and Shell converted to Calcedony.
(Original.)
Plate 42. V. I. pp. 264, 265. Note.
Fig. 1. Cast of a single chamber of Nautilus hexagon us, showing the simple curvatures of the edges of the transverse plates, and the place of the Siphuncle. (Original.)