Past and Present

In The Lost World, Doyle makes a clear distinction between past and present and how different and separated they are. For example on page 128, Doyle writes "The two things were separate and apart", referring to the two plateaus, which could symbolically represent past and present or civilization and the wild. Evolution, which Doyle mentions by referring to the missing link, involves building on the past and improving. So is Doyle contradicting himself? This joining and separation of past and present is also prevalent in our own world as seen in developing countries and even developed countries. Can the past and present really be separate? Can past and present coexist? Is the present built upon the past? Do things that happen in the past stay there?