xxviii 
LIST OF PLATES. 
or in the Miocene or Eocene formations, but occurs both in the 
Newer and OJder Pliocene strata. Mitra plicatula has been 
found only in the older Pliocene deposits. The Turbo rugosus 
was considered as exclusively Pliocene when selected by M. 
Deshayes, but M. Boue has since found it in the Miocene 
strata at Vienna and Moravia (see Tables, Appendix I. p. 26). 
Buccinum semistriatum is also a Miocene shell, but was in- 
serted as being peculiarly abundant in the Pliocene strata. 
Plate II. All the shells figured in this plate, except Car- 
dita Ajar, are very characteristic of the Miocene formations; 
that is to say, they are found in that period and no other. 
Cardita Ajar is also very common in the Miocene strata, but 
is also a Recent species. It has not yet been observed in any 
Pliocene deposit. 
Plate III. The species of shells figured in this plate are 
characteristic of the Eocene period, as being exclusively con- 
fined to deposits of that period, and for the most part abundant 
in them. 
Plate IV. The microscopic shells of the order Cephalo- 
poda, figured in this plate, are characteristic of the Eocene 
period, and are distinct from the microscopic shells of the Older 
Pliocene formations of Italy. The figures are from unpub- 
lished drawings by M. Deshayes, who has selected some of the 
most remarkable types of form. The reader will observe, that 
the minute points, figures 4, 8, 11, 14, and 18, indicate the 
natural size of the species which are represented. (For obser- 
vations on these shells see p. 251.) 
Plate V. Geological Map of the south-east of England, 
exhibiting the Denudation of the Weald. This map has been 
compiled in great part from Mr. Greenough's Geological Map 
of England, and Mr. Mantell's Map of the south-east of 
England. (Illustrations of Geol. of Sussex, and fossils of 
Tilgate Forest, 1827.) The eastern extremity of the ( denu- 
dation' is reduced from Mr. Murchison's Map of that district. 
(Geol. Trans., 2nd series, vol. ii. part i. plate 14.) The object 
of this map is fully explained in chapters xxi. and xxii. of this 
volume. 
