Mangawhai Rocks February 19, 2017 by Trish Whyte Leave a Comment Add to my favourite walks What made the big rock at surf beach white? What made large vertical columns on the shoreline ? Ancient archways and rock formations..walk, learn, discover on the Geology Walk ..one of my favourites !! Our Giant Causeway..columnar jointing on the shore line Ancient Basalt Archway Understanding our ancient rocks Geology walkers head to beach Be Sociable, Share!