At the end of your walk along the harbor, you will arrive at a free platform overlooking Reversing Falls. Be prepared to be amazed. Equally amazing are the geological formations below your feet and across the Saint John River. This is where two distant continents collided prehistory. The Avalon Terrane (also called the Caledonia Terrane) traveled here from Africa about 540 million years ago. The Brookville Terrane is even older. It originated in South America more than 700 million years ago. Some sections could be over one billion years old.