350 O. C. Marsh— Vertebrate Life in America. 
in the same beds, and probably all were provided with teeth. 
It is strange that the companions of these ancient toothed 
Birds should have been Pterodactyls without teeth. In the 
later Cretaceous beds of the Atlantic Coast, various remains 
of aquatic Birds have been found, but all are apparently dis- 
tinct from those of the West. The known genera of Ameri- 
ean Cretaceous birds are, Apatornis, Baptornis, Graculavus, 
Hesperornis, Ichthyornis, Laornis, Lestornis, Paleotringa and 
Telmatornis. These are represented by some twenty species. 
In Europe, but two species of Cretaceous birds are known, 
and both are based upon fragmentary specimens. 
During the Tertiary period, Birds were numerous in this 
country, and. all yet discovered. appear to have belonged to 
modern types. ‘The Kocene species described are mostly wading 
birds, but here, and in the later Tertiary deposits, some charac- 
teristic American forms make their appearance, strongly fore- 
shadowing our present avian fauna. ‘The extinct genera are the 
Kocene Utntornis, related to the Woodpeckers, and Aletornis, 
which includes several species of Waders. Among the existing 
genera found in our Tertiary beds are, Aquila, Bubo, Meleagris, 
Grus, Graculus, Puffinus, and Catarractes. The Great Auk 
(Alca impennis), which was once very abundant on our North- 
east Coast, has become extinct within a few years. 
wealth of our continent in the extinct forms of these groups, 
and thus to suggest what its actual life must have been. 
Although the Trias offers at present the first unquestioned 
evidence of true Reptiles, we certainly should not be justified 
in supposing for a moment that older forms did not exist. So 
too in considering the different groups of Reptiles, which seem 
to make their first appearance at certain horizons, flourish for 
a time, and then decline, or disappear, every day brings evidence 
to show that they are but fragments of the unraveled strands 
which converge in the past to form the mystic cord uniting all 
life. If the attempt is made to follow back any single thread, 
and thus trace the be e of a group, we are met by difficulties 
which the science of A can only partially remove. poate 
the anatomist constantly sees in the fragments which he studies 
hints of relationship which are to him sure prophecies of future 
discoveries. 
The genealogy of the Chelonia is at present unknown, and 
