BIRDS OF OLD 87 
to conclude that birds were abundant enough, 
but that we simply do not find them. 
Several eggs, too — or, rather, casts of eggs 
—have lately been found in the Cretaceous 
and Miocene strata of the West; and, as eggs 
and birds are usually associated, we are liable 
at any time to come upon the bones of the 
birds that laid them. 
To the writer's mind no thoroughly satisfac- 
tory explanation has been given for the scarci- 
ty of bird remains; but the reason commonly 
advanced is that, owing to their lightness, 
dead birds float for a much longer time than 
other animals, and hence are more exposed to 
the ravages of the weather and the attacks of 
carrion-feeding animals. It has also been said 
that the power of flight enabled birds to 
escape calamities that caused the death of con- 
temporary animals ; but all birds do not fly; 
and birds do fall victims to storms, cold, and 
starvation, and even perish of pestilence, like 
the Cormorants of Bering Island, whose ranks 
have twice been decimated by disease. 
It is true that where carnivorous animals 
abound, dead birds do disappear quickly ; and 
