GEOGRAPHICAL DISTRIBUTION OF ANIMALS
which is furnished by the camel family. This very peculiar family consists of two sections. One section includes the true camels of the Old World, whose present native habitat appears to be Asia, for the only wild camels now in existence are found solely in central Asia. The other section includes the much smaller, lighter, and more graceful guanacos, llamas, and like animals of South America. No one who has studied the anatomy of the camels can doubt for a moment that these two sections of the family are closely related, despite the great differences in their external appearance. The geological history of the family, as revealed by fossils, shows that, for a long time during the Tertiary period, North America was its only home, for during that time the camels appear to have inhabited no other continent. Each successive group of rocky strata in our western plains has yielded remains of its own characteristic types of camels, whose development toward the modern type may be followed through many almost imperceptible gradations, all presumably arising by ordinary procreation. Later in the Tertiary period the fossils record the arrival of camels in Asia, on the one hand, and in South America on the other; and finally, at a very late geological date, they completely disappeared from North America. Their passage from North America to Asia was made possible by the existence of land connection where we now find the shallow Bering Sea. This connection was often made and broken in past ages.
According to the doctrine of special creation the relationship between the true camels and the llamas is not real but purely ideal. The fossil camels, which seem to record successive steps of development, all moving in the same direction, record only successive, disconnected acts of sudden creation in a way of which we have had no experience, and
[ 83 ]
