The coloured map appended to my volume on Coral Reefs, led me to conclude that the great oceans are still mainly areas of subsidence, the great archipelagoes still areas of oscillations of level, and the continents areas of elevation.
But we have no reason to assume that things have thus remained from the beginning of the world.
Our continents seem to have been formed by a preponderance, during many oscillations of level, of the force of elevation.
But may not the areas of preponderant movement have changed in the lapse of ages? At a period long antecedent to the Cambrian epoch, continents may have existed where oceans are now spread out, and clear and open oceans may have existed where our continents now stand.