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XX. — Description of the Fossil Remains of a Mammal (Hyracotherium 

 leporinum) and of a Bird (Lithornis vulturinus) from the London Clay. 



By RICHARD OWEN, Esq., F.R.S., F.G.S., etc. 



[Read December 18, 1839.] 



Plate XXI. 



Until the present year, the remains of the highest organized animals which were 

 known to exist in the marine Eocene deposit called the London Clay, were those 

 of Reptiles and Fishes ; and the danger of founding conclusions in Palaeontology 

 from negative evidence was, perhaps, never more strikingly illustrated than by the 

 fact, that the first scientifically determined reUc of a warm-blooded animal from that 

 formation proved to belong not only to the Mammiferous class, but to the highest 

 order of that class, if Man be excepted. Besides the remains of the Quadrumanous 

 species just alluded to, there have since been discovered the teeth of Cheiroptera, 

 of Plantigrade and Digitigrade Carnivora, and of a species probably belonging to 

 the Marsupial order*. These most interesting fossils have been disinterred from 

 the London clay, underlying the coralline crag, near Kyson in Suffolk. 



I now propose to describe a fossil indicative of a new and extinct genus of the 

 Pachy dermal order, and the remains of a bird, both from the London clay at the 

 estuary of the Thames ; the latter fossils being the first of their class which have 

 been discovered in this member of the Eocene tertiary deposits. 



The Pachydermal fossil consists of a small mutilated cranium, about the size of 

 that of a Hare, containing the molar teeth of the upper jaw nearly perfect and the 

 sockets of the canines. 



It was discovered in the cliffs of Studd Hill, about a mile to the west of Heme 

 Bay, and was submitted to my examination by William Richardson, Esq., by whom 

 it has since been presented to the Museum of the Royal College of Surgeons. f 



* Annals of Natural History, Nov. 1839. 



t For an account of the discovery of the Hyracotherium and a description of the beds near Heme 

 Bay, see Mr. Richardson's paper, />05fea, p. 211. 



2 d2 



