CHAP, VIII. ] BIRDS. 161 
as indications of past changes in physical geography. A large 
proportion of the remains belong to aquatic or wading types, 
and as these have now often a world-wide range, the occurrence 
of extinct forms can have little bearing on our present inquiry. 
There are, however, a few interesting cases of extinct land-birds 
belonging to groups now quite strangers to the country in which 
they are found; and others scarcely less interesting, in which 
groups now peculiar to certain areas are shown to have been 
preceded by allied species or genera of gigantic size. 
Palearctic Region and N. India.—In the caves and other 
Post-Pliocene deposits of these countries, the remains of birds 
almost all belong to genera now inhabiting the same districts. 
Almost the only exceptions are, the great auk and the 
capercailzie, already mentioned as being found in the Danish 
mounds ; the latter bird, with Tetrao albus, in Italian caverns; 
and aspecies of pheasant (Phasianus) said to have occurred in 
the Post- Pliocene of France, considerably west of the existing 
range of the genus in a wild state. 
In the preceding Pliocene deposits, but few remains have 
been found, and all of existing genera but one, a gallinaceous 
bird (Gallus bravardi) allied to the domestic fowl and peacock. 
The Miocene beds of France and Central Europe have pro- 
duced many more remains of birds, but these, too, are mostly of 
existing European genera, though there are some notable excep- 
tions. Along with forms undistinguishable from crows (Corvus), 
shrikes (Lanius), wagtails (Motacilla), and woodpeckers (Picus), 
are found remains allied to the Oriental edible-nest swift (Col- 
localia) and Trogon; a parrot resembling the African genus 
Psittacus; an extinct form WNecrornis, perhaps allied to the 
plantain-eaters (Musophaga) ; Homalophus, doubtfully allied to 
woodpeckers, and Zimnatornis to the hoopoes. The gallina- 
ceous birds are represented by three species of pheasants, some 
very close to the domesticated species; Paleoperdix allied to the 
partridges ; and Paleortyx, small birds allied to the American 
genus Ortyx, but with larger wings. There are also species of 
Pterocles allied to living birds, and a small pigeon. There are 
numerous living genera of Accipitres; such as eagle (Aquila), 
