“We have never solved the mystery of ice ages in the tropics, nor the equally strange mystery of the growth of corals and warm-climate flora in the polar zones. [...] It became obvious to me, as I reviewed these problems, and went back over the controversies that had marked their consideration, that a sort of common denominator was present. [...] [S]omebody usually tried to explain the particular problem in terms of changes in the position of the poles. This, I found, was the common denominator. The authors of such theories, unfortunately, were never able to prove their assumptions. The opponents of the notion of polar change always managed to point out fallacies that seemed decisive. At the same time, no one was able to reconcile all the evidence in the different fields with the idea that the poles have always been situated where they are now on the earth's surface. The theory here presented would solve these problems by supposing changes in the positions of the poles. Campbell has suggested that the changes have occurred not by reason of changes in the position of the earth's axis, but simply through a sliding of its crust.” MysteryEvidenceProofControversyTheoriesPolesIce Ages Book:Earth's Shifting Crust: A Key To Some Basic Problems Of Earth Science Source: Earth's Shifting Crust: A Key To Some Basic Problems Of Earth Science