"Sometime during the many millions of years that have elapsed since mammalian faunas came into existence, some sort of island crossed from West Africa to South America"

This quote by Louis Leakey suggests that throughout the numerous years since mammals first appeared, some sort of land bridge have to have existed in between West Africa and also South America. This bridge would certainly have allowed animals to move from one continent to the other, permitting the spread of species and also the diversity of the animal fauna. This bridge might have been a natural land bridge, or it might have been produced by a geological occasion such as an earthquake or volcanic eruption. Whatever the reason, this bridge has to have existed at some point in the past in order for the animals to have actually spread out from one continent to the other. This quote highlights the significance of geological events in shaping the advancement of types as well as the variety of life on Earth.