THE scientific Reader will feel that much value has been added to the present work, from the whole of the Palaeontology, during its progress through the Press, having had the great advantage of passing under the revision of Mr. Broderip, and from the botanical part having been submitted to Mr. Robert Brown. I have also to acknowledge my obligations to Mr. Clift for his important assistance in the anatomy of the Megatherium; to Professor Agassiz of Neuchatel for his unreserved communications of his discoveries relating to Fossil Fishes; to Mr. Owen for his revision of some parts of my Chapter on Mollusks; and. to Mr. James Sowerby for his assistance in engraving most of my figures of radiated animals, and some of those of Mollusks.
To all these Gentlemen I feel it my duty thus to offer my public acknowledgments.
Many obligations to other scientific friends are also acknowledged in the course of the work.
The Wood-cuts have been executed by Mr. Fisher and Mr. Byfield, and most of the Steel plates of Mollusks by Mr. Zeitter.
