86 TERTIARY SERIES. 
Besides the many extinct species, and extinct 
genera of Mammalia that are enumerated in 
this list, the occurrence of nine or ten extinct 
species of fossil Birds in the Eocene period of 
the tertiary series, forms a striking phenomenon 
in the history of organic remains.* 
In this small number of species, we have 
seven genera ; and these afford examples of four, 
out of the six great Orders into which the exist- 
ing Class of Birds is divided, viz. Accipitres, 
Gallinaceae, Grallae, and Palmipedes. Even the 
eggs of aquatic birds have been preserved in the 
lacustrine formations of Cournon, in Auvergne-t 
* The only remains of Birds yet noticed in strata of the Se- 
condary series are the bones of some "Wader, larger than a com- 
mon Heron, found by Mr. Mantell in the fresh-water formation 
of Tilgate Forest. The bones at Stonesfield, once supposed to 
be derived from Birds, are now referred to Pterodactyles. A 
discovery has recently been made in America by Professor Hitch- 
cock, of the footsteps of Birds in the New Red sandstone of the 
valley of the Connecticut, which he refers to at least seven 
species, all apparently Waders, having very long legs, and of va- 
rious dimensions from the size of a Snipe, to twice the size of an 
Ostrich. (See PI. 26\ 26\) 
f In the same Eocene formation with these eggs, there occur 
also the remains of two species of Anoplotherium, a Lophiodon, 
an Anthracrotherium, a Hippopotamus, a ruminating animal, a 
Dog, a Martin, a Lagomys, a Rat, one or two Tortoises, a Cro- 
codile, a Serpent or Lizard, and three or four species of Birds. 
These remains are dispersed singly, as if the animals from which 
they were derived had decomposed slowly and at different in- 
tervals, and thus fragments of their bodies had been lodged 
irregularly in various parts of the bottom of the ancient lake : 
these bones are sometimes broken, but never rolled. 
