PREFACE. 
V 
A large number of new species from the Cretaceous group have 
been described and figured by Mr. J. Sowerby in the Appendix to 
Dr. Fitton’s interesting memoir ^ On the beds between the Chalk 
and Oolite/ Geol. Trans, vol. iv. The publication of the ^ Palaeon- 
tologie Frangaise/ by M. d’Orbigny, has also thrown considerable 
light on the fossils of this aera^ to which many interesting additions 
may be expected in the forthcoming work of Mr. Dixon of Wor- 
thing. A considerable number of new fossils have recently been 
procured from the London Clay in the neighbourhood of the me- 
tropolis^ and of Barton^ and the Isle of Sheppy^ and which are to 
be found in the extensive cabinets of Messrs. Bowerbank, We- 
therellj and others ; illustrations of these will probably be published 
in a separate monograph^ or in the continuation of the ^ Mineral 
Conchology.^ As belonging to this formation^ the Author is enabled 
to insert several new species from Bracklesham Bay^ in the rich 
collection of Mr. Edwards^ and which have been described in Des- 
hayes^ ^ Coquilles Fossiles des Environs de Paris/ 
With regard to the fossils of the Crag, geologists are much in- 
debted to the active researches of Mr. Searles V. Wood, who has 
for some years devoted his attention to these formations, and has 
published in the ^Annals of Natural History,’ accompanied by a 
few illustrations, an extensive list of species belonging to them. 
The Pleistocene deposits*, including the Raised Beaches of En- 
gland and Scotland, have been more particularly examined by Mr. 
J. Smith of Jordan Hill, who has published, in the Wernerian 
Memoirs L vol. viii., an extended list of species obtained from the 
basin of the Clyde and other localities ; and a subsequent communi- 
cation to the Geological Society of London, by the Rev. D. Lands- 
borough,has also added considerable information as to these deposits. 
The list of Fossil Fishes has been compiled from the ^Poissons 
Fossiles’ of Agassiz; but a large number of new species from the 
Old Red Sandstone, Oolite, London Clay, &c. have not yet been 
described by that competent naturalist. The Author is, however, 
under great obligations to Sir Philip de Grey Egerton, to whose 
unsolicited kindness he is indebted for a complete revision of this 
portion of the Catalogue, as well as for the addition of many new 
species, which form a part either of the well-known collection of 
Sir Philip Egerton, or of that of Lord Enniskillen. 
* Respecting the shells of the Pleistocene freshwater deposits, much valuable 
information has been afforded by Mr. S. P. Woodward. 
t The descriptions of the new species were prepared by Capt. T. Brown. 
