The Taieri River cuts through 100 million-year-old breccia containing an almost 1 km layer of greywacke, schist, cobble and pebble breccia conglomerate. This breccia extends as a strip right down the Taieri Plains, to the inland side of the coastal hills as far south as Milton. After flowing through the flood-prone Taieri Plains, the river cuts through the coastal hills to disgorge into the Pacific Ocean by the picturesque fishing village of Taieri Mouth.
– From DoC hard copy information sheet