220 EXTINCT MONSTERS 
and a strongly keeled sternum for the attachment of muscles with 
which to work its wing. It was about the size of a rock-pigeon. 
The jaws were armed with teeth placed in distinct sockets, as in 
some extinct reptiles. The wing bones show that it possessed 
considerable powers of flight. Here we may note that the Cre- 
taceous birds at present known (some twenty species or more) 
were apparently all aquatic forms, which, of course, are most 
likely to be preserved in marine deposits, while the Jurassic 
Archeopteryx was a land bird. 
Remains of Cretaceous birds were first found in the Upper 
Greensand of Cambridge, and on these bones the genus Enaliornis 
has been founded. In its head and neck it resembled the divers. 
Several portions of fossil birds have been discovered in the 
London Clay deposit of the Isle of Sheppey. One of these, the 
Dasornis, represented by a single skull, was as large as an ostrich, 
and probably closely related to that bird. Another, the Argillornis, 
rivalled the albatross in size. A third, the Odontopteryx (toothed 
bird), has a powerful serrated bill, well adapted for seizing its 
fishy prey. In the same case in the Natural History Museum 
may be seen casts of the limb-bones of a large bird, the 
Gastornis parisiensis, from Eocene strata near Paris; also casts 
of two leg-bones of another equally large bird, allied to the 
above, discovered in the Eocene strata near Croydon, viz. 
Gastornis Klaasseni. A restoration of the French bird’s skeleton 
is shown in Fig. 83. The genus must have been as large 
as an ostrich, but more robust, with some signs of affinity with 
geese, as well as to ratite birds such as the ostrich. 
Many other orders of birds are more or less represented by 
fossil remains from Tertiary strata, but in most cases not so 
perfectly as to warrant description here. For instance, the 
Pliocene strata of the Sivalik hills have yielded bones of 
