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 AVest ; 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 



