THE FOSSIL FISHES 



ENGLISH WEALDEN AND PUEBECK FORMATIONS. 



INTRODUCTION. 



Ti{E fishes of the Wealden and Piirbeck formations are of special interest as 

 representing the latest of the typical Jurassic faunas. Certain families and genera 

 range even to Upper Cretaceous horizons, bnt here they are rare and mingled 

 with a multitude of more modern fishes. The great estuary in which the Wealden 

 and Purbeck beds were deposited must have opened into a sea in which there 

 were none but Jurassic forms ; and the only noteworthy features of the fishes 

 discovered in these formations are certain marks of senility and an occasional 

 dwarfing of the species. The remains are usually fragmentary, though most of 

 the ganoids are now known by nearly complete specimens, and there are many 

 pieces showing important osteological characters. The fragments in the Wealden 

 are often much waterworn and abraded, while the better preserved fishes in the 

 Purbeck limestones have frequently been so much crushed that the details of their 

 structure are obscured. 



Fish-remains seem to have been first noticed in the Wealden formations by 

 Dr. Gideon A. Mantell, who described them in his early works. ^ A fine collection 

 was also made on the Sussex coast by Mr. Samiiel H. Beckles, and important 

 series of Wealden specimens have been obtained during more recent years by 

 Messrs. Charles Dawson, Philip Rufford, E. J. Baily, and Reginald W. Hooley. 

 The Mantell, Beckles, Dawson, and Rufford collections are now in the British 

 Museum, while that of Mr. Baily is in the Hastings Museum. Fossil fishes from 

 the Purbeck Beds of Swanage, Dorset, were noticed at least so long ago as 1816 2 

 and are preserved in many museums. They are especially well represented in the 

 British Museum, the Museum of Practical Geology, and the Dorset County 



1 G. A. Mantell, ' The Fossils of the South Downs ' (1822), pp. 45, 46 (description only) ; 'Illus- 

 ti-ations of the Geology of Sussex ' (1827). 



2 T. Webster in H. C. Engiefield, 'The Isle of Wight ' (London, 1816), p. 192. 



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