 Caps feature cliff erosion, including sea caves, marine arches, sea stacks, sea trenches, and abrasion platforms, while sea caves are dominant.The less prevailing sedimentary landforms are mainly seen in the inlets and are characteristic of pebble beaches.On account of the geological distinctiveness of Dongyin, in “Natural Landscapes and Resources Survey in the Matsu Islands” (), conducted in 2000 by National Taiwan University Professor Ging-Chan Lin, twelve out of eighteen sights on the island were rated A.